21 Hospital Dr Suite 250
Palm Coast FL 32164
Medical School: Other - 1980
Accepts Medicare: Yes
Participates In eRX: Yes
Participates In PQRS: No
Participates In EHR: No
License #: 0051680
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Awards & Recognitions
Dr. John Zak is associated with these group practices
|HCPCS Code||Description||Average Price||Average Price
Allowed By Medicare
|HCPCS Code:45380||Description:Colonoscopy and biopsy||Average Price:$838.00||Average Price Allowed
|HCPCS Code:45378||Description:Diagnostic colonoscopy||Average Price:$699.00||Average Price Allowed
|HCPCS Code:45384||Description:Lesion remove colonoscopy||Average Price:$704.62||Average Price Allowed
|HCPCS Code:45385||Description:Lesion removal colonoscopy||Average Price:$641.13||Average Price Allowed
|HCPCS Code:43239||Description:Upper gi endoscopy biopsy||Average Price:$358.97||Average Price Allowed
|HCPCS Code:99205||Description:Office/outpatient visit new||Average Price:$390.00||Average Price Allowed
|HCPCS Code:99223||Description:Initial hospital care||Average Price:$386.48||Average Price Allowed
|HCPCS Code:43246||Description:Place gastrostomy tube||Average Price:$440.50||Average Price Allowed
|HCPCS Code:99232||Description:Subsequent hospital care||Average Price:$205.75||Average Price Allowed
|HCPCS Code:99204||Description:Office/outpatient visit new||Average Price:$297.17||Average Price Allowed
|HCPCS Code:99214||Description:Office/outpatient visit est||Average Price:$233.48||Average Price Allowed
|HCPCS Code:43235||Description:Uppr gi endoscopy diagnosis||Average Price:$255.13||Average Price Allowed
|HCPCS Code:99213||Description:Office/outpatient visit est||Average Price:$156.26||Average Price Allowed
|HCPCS Code:99233||Description:Subsequent hospital care||Average Price:$182.27||Average Price Allowed
HCPCS Code Definitions
- Subsequent hospital care, per day, for the evaluation and management of a patient, which requires at least 2 of these 3 key components: A detailed interval history; A detailed examination; Medical decision making of high complexity. Counseling and/or coordination of care with other physicians, other qualified health care professionals, or agencies are provided consistent with the nature of the problem(s) and the patient's and/or family's needs. Usually, the patient is unstable or has developed a significant complication or a significant new problem. Typically, 35 minutes are spent at the bedside and on the patient's hospital floor or unit.
- Subsequent hospital care, per day, for the evaluation and management of a patient, which requires at least 2 of these 3 key components: An expanded problem focused interval history; An expanded problem focused examination; Medical decision making of moderate complexity. Counseling and/or coordination of care with other physicians, other qualified health care professionals, or agencies are provided consistent with the nature of the problem(s) and the patient's and/or family's needs. Usually, the patient is responding inadequately to therapy or has developed a minor complication. Typically, 25 minutes are spent at the bedside and on the patient's hospital floor or unit.
- Initial hospital care, per day, for the evaluation and management of a patient, which requires these 3 key components: A comprehensive history; A comprehensive examination; and Medical decision making of high complexity. Counseling and/or coordination of care with other physicians, other qualified health care professionals, or agencies are provided consistent with the nature of the problem(s) and the patient's and/or family's needs. Usually, the problem(s) requiring admission are of high severity. Typically, 70 minutes are spent at the bedside and on the patient's hospital floor or unit.
- Esophagogastroduodenoscopy, flexible, transoral; with directed placement of percutaneous gastrostomy tube
- Office or other outpatient visit for the evaluation and management of an established patient, which requires at least 2 of these 3 key components: A detailed history; A detailed examination; Medical decision making of moderate complexity. Counseling and/or coordination of care with other physicians, other qualified health care professionals, or agencies are provided consistent with the nature of the problem(s) and the patient's and/or family's needs. Usually, the presenting problem(s) are of moderate to high severity. Typically, 25 minutes are spent face-to-face with the patient and/or family.
- Office or other outpatient visit for the evaluation and management of a new patient, which requires these 3 key components: A comprehensive history; A comprehensive examination; Medical decision making of high complexity. Counseling and/or coordination of care with other physicians, other qualified health care professionals, or agencies are provided consistent with the nature of the problem(s) and the patient's and/or family's needs. Usually, the presenting problem(s) are of moderate to high severity. Typically, 60 minutes are spent face-to-face with the patient and/or family.
- Office or other outpatient visit for the evaluation and management of an established patient, which requires at least 2 of these 3 key components: An expanded problem focused history; An expanded problem focused examination; Medical decision making of low complexity. Counseling and coordination of care with other physicians, other qualified health care professionals, or agencies are provided consistent with the nature of the problem(s) and the patient's and/or family's needs. Usually, the presenting problem(s) are of low to moderate severity. Typically, 15 minutes are spent face-to-face with the patient and/or family.
- Colonoscopy, flexible, proximal to splenic flexure; with removal of tumor(s), polyp(s), or other lesion(s) by hot biopsy forceps or bipolar cautery
- Esophagogastroduodenoscopy, flexible, transoral; with biopsy, single or multiple
- Colonoscopy, flexible, proximal to splenic flexure; diagnostic, with or without collection of specimen(s) by brushing or washing, with or without colon decompression (separate procedure)
- Colonoscopy, flexible, proximal to splenic flexure; with biopsy, single or multiple
- Office or other outpatient visit for the evaluation and management of a new patient, which requires these 3 key components: A comprehensive history; A comprehensive examination; Medical decision making of moderate complexity. Counseling and/or coordination of care with other physicians, other qualified health care professionals, or agencies are provided consistent with the nature of the problem(s) and the patient's and/or family's needs. Usually, the presenting problem(s) are of moderate to high severity. Typically, 45 minutes are spent face-to-face with the patient and/or family.
- Colonoscopy, flexible, proximal to splenic flexure; with removal of tumor(s), polyp(s), or other lesion(s) by snare technique
- Esophagogastroduodenoscopy, flexible, transoral; diagnostic, including collection of specimen(s) by brushing or washing, when performed (separate procedure)
Medical Malpractice Cases
Flagler County Florida
Case Number: 2009CA001658
Incident Date: 11/29/2006
Settlemnt Date: 04/27/2010
Medical Board Sanctions
Lic Discip By Fed/Other State
New York State Board Of Medical Conduct
Pract Below Prev Peer Standard
Florida Department Of Health
Quality Of Care
Florida Hospital Flagler
Cardiovascular Disease (Cardiology)
*These referrals represent the top 10 that Dr. Zak has made to other doctors
Soil microbial and nutrient responses to 7Â years of seasonally altered precipitation in a Chihuahuan Desert grassland. - Global change biology
Soil microbial communities in Chihuahuan Desert grasslands generally experience highly variable spatiotemporal rainfall patterns. Changes in precipitation regimes can affect belowground ecosystem processes such as decomposition and nutrient cycling by altering soil microbial community structure and function. The objective of this study was to determine if increased seasonal precipitation frequency and magnitude over a 7-year period would generate a persistent shift in microbial community characteristics and soil nutrient availability. We supplemented natural rainfall with large events (one/winter and three/summer) to simulate increased precipitation based on climate model predictions for this region. We observed a 2-year delay in microbial responses to supplemental precipitation treatments. In years 3-5, higher microbial biomass, arbuscular mycorrhizae abundance, and soil enzyme C and P acquisition activities were observed in the supplemental water plots even during extended drought periods. In years 5-7, available soil P was consistently lower in the watered plots compared to control plots. Shifts in soil P corresponded to higher fungal abundances, microbial C utilization activity, and soil pH. This study demonstrated that 25% shifts in seasonal rainfall can significantly influence soil microbial and nutrient properties, which in turn may have long-term effects on nutrient cycling and plant P uptake in this desert grassland.Â© 2013 John Wiley & Sons Ltd.
Natural transformation as a mechanism of horizontal gene transfer among environmental Aeromonas species. - Systematic and applied microbiology
Aeromonas species are common inhabitants of aquatic environments and relevant as human pathogens. Their potential as pathogens may be related in part to lateral transfer of genes associated with toxin production, biofilm formation, antibiotic resistance, and other virulence determinants. Natural transformation has not been characterized in aeromonads. DNA from wild-type, prototrophic strains that had been isolated from environmental sources was used as donor DNA in transformation assays with auxotrophs as the recipients. Competence was induced in 20% nutrient broth during the stationary phase of growth. Optimal transformation assay conditions for one chosen isolate were in Tris buffer with magnesium or calcium, pH 5-8, and a saturating concentration of 0.5 Î¼g of DNA per assay (3.3 ng of DNA Î¼lâ»Â¹) at 30Â°C. Sodium was also required and could not be replaced with ammonium, potassium, or lithium. The maximal transformation frequency observed was 1.95 Ã— 10â»Â³ transformants (recipient cell)â»Â¹. A survey of environmental Aeromonas auxotrophic recipients (n=37), assayed with donor DNA from other wild-type environmental aeromonads under optimal assay conditions, demonstrated that 73% were able to act as recipients, and 100% were able to act as donors to at least some other aeromonads. Three different transformation groups were identified based on each isolates' ability to transform other strains with its DNA. The transformation groups roughly corresponded to phylogenetic groups. These results demonstrate that natural transformation is a general property of Aeromonas environmental isolates with implications for the genetic structures of coincident Aeromonas populations.Copyright Â© 2013 Elsevier GmbH. All rights reserved.
Bacterial community dynamics in high and low bioavailability soils following laboratory exposure to a range of hexahydro-1,3,5-trinitro-1,3,5-triazine concentrations. - Environmental toxicology and chemistry / SETAC
Few studies have examined the potential long-term effects of high concentrations of hexahydro-1,3,5-trinitro-1,3,5-triaxine (RDX) on bacterial communities in soil. In the present study, a sandy loam soil and a silt loam soil (high and low bioavailability, respectively) were artificially contaminated with RDX (0, 50, 500, 1,500, 5,000, 10,000, and 15,000 mg/kg soil). Bacterial communities from each treatment were monitored over 63 d to characterize the effects of RDX exposure on bacterial activity, biomass, functional diversity (Biolog microtiter plates), and structural diversity (denaturing gradient gel electrophoresis of 16S rDNA). Bacterial communities native to the high bioavailability soil were inherently different than bacterial communities native to the silt loam soil, not only in terms of bacterial activity and biomass, but also in terms of bacterial community functional and structural diversity. Soil RDX contamination was correlated with decreased bacterial biomass in the silt loam soil treatments and with decreased bacterial activity in the sandy loam soil treatments on day 7. Soil RDX contamination did not cause a significant shift in the functional diversity of the bacterial communities native to the silt loam soil, but was correlated with a shift in identities of substrates used by bacterial communities native to the sandy loam soil on day 7. Bacterial community structure was insensitive to the gradient of RDX concentrations at the beginning of the incubation. However, the identities of carbon substrates used by bacterial communities in both soil types were affected by long-term incubation with RDX.
Choline and osmotic-stress tolerance induced in Arabidopsis by the soil microbe Bacillus subtilis (GB03). - Molecular plant-microbe interactions : MPMI
Choline (Cho) is an essential nutrient for humans as well as the precursor of glycine betaine (GlyBet), an important compatible solute in eukaryotes that protects cells from osmotic stress caused by dehydrating conditions. The key enzyme for plant Cho synthesis is phosphoethanolamine N-methyltransferase (PEAMT), which catalyzes all three methylation steps, including the rate-limiting N-methylation of phosphoethanolamine. Herein, we report that the beneficial soil bacterium Bacillus subtilis (strain GB03) enhances Arabidopsis Cho and GlyBet synthesis associated with enhanced plant tolerance to osmotic stress. When stressed with 100 mM exogenous mannitol, GB03-exposed plants exhibit increased transcript level of PEAMT compared with stressed plants without bacterial exposure. Endogenous Cho and GlyBet metabolite pools were elevated by more than two- and fivefold, respectively, by GB03 treatment, consistent with increased stress tolerance. Moreover, in the xipotl mutant line with reduced Cho production, a loss of GB03-induced drought tolerance is observed. Osmotic-stressed plants with or without GB03 exposure show similar levels of abscsisic acid (ABA) accumulation in both shoots and roots, suggesting that GB03-induced osmoprotection is ABA independent. GB03 treatment also improves drought tolerance in soil-grown plants as characterized by phenotypic comparisons, supported by an elevated accumulation of osmoprotectants. These results provide a biological strategy to enhance Cho biosynthesis in plants and, in turn, increase plant tolerance to osmotic stress by elevating osmoprotectant accumulation.
Precipitation magnitude and timing differentially affect species richness and plant density in the sotol grassland of the Chihuahuan Desert. - Oecologia
Arid and semi-arid environments are dynamic ecosystems with highly variable precipitation, resulting in diverse plant communities. Changes in the timing and magnitude of precipitation due to global climate change may further alter plant community composition in desert regions. In this study, we assessed changes in species richness and plant density at the community, functional group, and species level in response to variation in the magnitude of natural seasonal precipitation and 25% increases in seasonal precipitation [e.g., supplemental watering in summer, winter, or summer and winter (SW)] over a 5-year period in a sotol grassland in the Chihuahuan Desert. Community species richness was higher with increasing winter precipitation while community plant density increased with greater amounts of winter and summer precipitation, suggesting winter precipitation was important for species recruitment and summer precipitation promoted growth of existing species. Herb and grass density increased with increasing winter and summer precipitation, but only grass density showed a significant response to supplemental watering treatments (SW treatment plots had higher grass density). Shrubs and succulents did not exhibit changes in richness or density in response to natural or supplemental precipitation. In this 5-year study, changes in community species richness and density were driven by responses of herb and grass species that favored more frequent small precipitation events, shorter inter-pulse duration, and higher soil moisture. However, due to the long life spans of the shrub and succulent species within this community, 5 years may be insufficient to accurately evaluate their response to variable timing and magnitude of precipitation in this mid-elevation grassland.
Linking microbial community structure and function to seasonal differences in soil moisture and temperature in a Chihuahuan desert grassland. - Microbial ecology
Global and regional climate models predict higher air temperature and less frequent, but larger precipitation events in arid regions within the next century. While many studies have addressed the impact of variable climate in arid ecosystems on plant growth and physiological responses, fewer studies have addressed soil microbial community responses to seasonal shifts in precipitation and temperature in arid ecosystems. This study examined the impact of a wet (2004), average (2005), and dry (2006) year on subsequent responses of soil microbial community structure, function, and linkages, as well as soil edaphic and nutrient characteristics in a mid-elevation desert grassland in the Chihuahuan Desert. Microbial community structure was classified as bacterial (Gram-negative, Gram-positive, and actinomycetes) and fungal (saprophytic fungi and arbuscular mycorrhiza) categories using (fatty acid methyl ester) techniques. Carbon substrate use and enzymic activity was used to characterize microbial community function annually and seasonally (summer and winter). The relationship between saprophytic fungal community structure and function remained consistent across season independent of the magnitude or frequency of precipitation within any given year. Carbon utilization by fungi in the cooler winter exceeded use in the warmer summer each year suggesting that soil temperature, rather than soil moisture, strongly influenced fungal carbon use and structure and function dynamics. The structure/function relationship for AM fungi and soil bacteria notably changed across season. Moreover, the abundance of Gram-positive bacteria was lower in the winter compared to Gram-negative bacteria. Bacterial carbon use, however, was highest in the summer and lower during the winter. Enzyme activities did not respond to either annual or seasonal differences in the magnitude or timing of precipitation. Specific structural components of the soil microbiota community became uncoupled from total microbial function during different seasons. This change in the microbial structure/function relationship suggests that different components of the soil microbial community may provide similar ecosystem function, but differ in response to seasonal temperature and precipitation. As soil microbes encounter increased soil temperatures and altered precipitation amounts and timing that are predicted for this region, the ability of the soil microbial community to maintain functional resilience across the year may be reduced in this Chihuahuan Desert ecosystem.
PCR-DGGE comparison of bacterial community structure in fresh and archived soils sampled along a Chihuahuan Desert elevational gradient. - Microbial ecology
The polymerase chain reaction coupled with denaturing gradient gel electrophoresis (PCR-DGGE) has been used widely to determine species richness and structure of microbial communities in a variety of environments. Researchers commonly archive soil samples after routine chemical or microbial analyses, and applying PCR-DGGE technology to these historical samples offers evaluation of long-term patterns in bacterial species richness and community structure that was not available with previous technology. However, use of PCR-DGGE to analyze microbial communities of archived soils has been largely unexplored. To evaluate the stability of DGGE patterns in archived soils in comparison with fresh soils, fresh and archived soils from five sites along an elevational gradient in the Chihuahuan Desert were compared using PCR-DGGE of 16S rDNA. DNA from all archived samples was extracted reliably, but DNA in archived soils collected from a closed-canopy oak forest site could not be amplified. DNA extraction yields were lower for most archived soils, but minimal changes in bacterial species richness and structure due to archiving were noted in bacterial community profiles from four sites. Use of archived soils to determine long-term changes in bacterial community structure via PCR-DGGE appears to be a viable option for addressing microbial community dynamics for particular ecosystems or landscapes.
Precipitation timing and magnitude differentially affect aboveground annual net primary productivity in three perennial species in a Chihuahuan Desert grassland. - The New phytologist
Plant productivity in deserts may be more directly responsive to soil water availability than to precipitation. However, measurement of soil moisture alone may not be enough to elucidate plant responses to precipitation pulses, as edaphic factors may influence productivity when soil moisture is adequate. The first objective of the study was to determine the responses of the aboveground annual net primary productivity (ANPP) of three perennial species (from different functional groups) in a Chihuahuan Desert grassland to variation in natural precipitation (annual and seasonal) and a 25% increase in seasonal precipitation (supplemental watering in summer and winter). Secondly, ANPP responses to other key environmental and soil parameters were explored during dry, average, and wet years over a 5-yr period. ANPP predictors for each species were dynamic. High ANPP in Dasylirion leiophyllum was positively associated with higher soil NH(4)-N and frequent larger precipitation events, while that in Bouteloua curtipendula was positively correlated with frequent small summer precipitation events with short inter-pulse periods and supplemental winter water. Opuntia phaeacantha was responsive to small precipitation events with short inter-pulse periods. Although several studies have shown ANPP increases with increases in precipitation and soil moisture in desert systems, this was not observed here as a universal predictor of ANPP, particularly in dry years.
Soil microbial community response to drought and precipitation variability in the Chihuahuan Desert. - Microbial ecology
Increases in the magnitude and variability of precipitation events have been predicted for the Chihuahuan Desert region of West Texas. As patterns of moisture inputs and amounts change, soil microbial communities will respond to these alterations in soil moisture windows. In this study, we examined the soil microbial community structure within three vegetation zones along the Pine Canyon Watershed, an elevation and vegetation gradient in Big Bend National Park, Chihuahuan Desert. Soil samples at each site were obtained in mid-winter (January) and in mid-summer (August) for 2 years to capture a component of the variability in soil temperature and moisture that can occur seasonally and between years along this watershed. Precipitation patterns and amounts differed substantially between years with a drought characterizing most of the second year. Soils were collected during the drought period and following a large rainfall event and compared to soil samples collected during a relatively average season. Structural changes within microbial community in response to site, season, and precipitation patterns were evaluated using fatty acid methyl ester (FAME) and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analyses. Fungal FAME amounts differed significantly across seasons and sites and greatly outweighed the quantity of bacterial and actinomycete FAME levels for all sites and seasons. The highest fungal FAME levels were obtained in the low desert scrub site and not from the high elevation oak-pine forests. Total bacterial and actinomycete FAME levels did not differ significantly across season and year within any of the three locations along the watershed. Total bacterial and actinomycete FAME levels in the low elevation desert-shrub and grassland sites were slightly higher in the winter than in the summer. Microbial community structure at the high elevation oak-pine forest site was strongly correlated with levels of NH4+-N, % soil moisture, and amounts of soil organic matter irrespective of season. Microbial community structure at the low elevation desert scrub and sotol grasslands sites was most strongly related to soil pH with bacterial and actinobacterial FAME levels accounting for site differences along the gradient. DGGE band counts of amplified soil bacterial DNA were found to differ significantly across sites and season with the highest band counts found in the mid-elevation grassland site. The least number of bands was observed in the high elevation oak-pine forest following the large summer-rain event that occurred after a prolonged drought. Microbial responses to changes in precipitation frequency and amount due to climate change will differ among vegetation zones along this Chihuahuan Desert watershed gradient. Soil bacterial communities at the mid-elevation grasslands site are the most vulnerable to changes in precipitation frequency and timing, while fungal community structure is most vulnerable in the low desert scrub site. The differential susceptibility of the microbial communities to changes in precipitation amounts along the elevation gradient reflects the interactive effects of the soil moisture window duration following a precipitation event and differences in soil heat loads. Amounts and types of carbon inputs may not be as important in regulating microbial structure among vegetation zones within in an arid environment as is the seasonal pattern of soil moisture and the soil heat load profile that characterizes the location.
Characterization of the structural and functional diversity of indigenous soil microbial communities in smelter-impacted and nonimpacted soils. - Environmental toxicology and chemistry / SETAC
A century of mining and smelting activity at the Anaconda Smelter site in Anaconda, Montana, USA, has contaminated the surrounding soils and groundwater with metals. Soil microbial communities from six smelter-impacted sites and a nonimpacted site were compared to determine the long-term effects of a gradient of metal concentrations on microbial activity, biomass, functional diversity (Biolog microtiter plates), and structural diversity (denaturant gradient gel electrophoresis of 16S ribosomal DNA). Microbial activity and biomass were decreased in the smelter-impacted soils. Likewise, the functional and structural diversity of the microbial communities native to the smelter-impacted soils were shifted, relative to the microbial community, from the nonimpacted site. These shifts were significantly correlated with soil metal concentration and several soil physicochemical properties (pH, organic matter, NO(3), NH(4), etc.), which provides evidence of the importance of many environmental variables on microbial community dynamics in soils. Preliminary evidence of functional redundancy was observed within microbial communities native to the smelter-impacted sites, based on overlapping carbon substrate utilization patterns. However, due to culture-based selection bias, redundancy pertains only to a subset of the community and may not be ecologically relevant. Nevertheless, the effects of metal contamination on microbial communities in the present study are pronounced and results provide preliminary insight into the complex relationship between soil microbial community structure and function in anthropogenically disturbed soils.
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