Kinetics of Sugar Transport and Phosphorylation Influence Glucose and Fructose Cometabolism by Zymomonas mobilis

The competitive inhibition of fructokinase by glucose has been proposed as the mechanism by which Zymomonas mobilis preferentially consumes glucose from mixtures of glucose and fructose and accumulates fructose when growing on sucrose. In this study, incorporation of radioactive fructose into biomass was used as a measure of fructose catabolism. It was determined that the rate of fructose incorporation by Z. mobilis CP4 was somewhat lower in the presence of an equimolar concentration of glucose but that the inhibition of fructokinase by glucose was not nearly as severe in vivo as was predicted from in vitro studies. Interestingly, addition of glucose to a culture of Z. mobilis CP4-M2, a glucokinaseless mutant, resulted in an immediate and nearly complete inhibition of fructose incorporation. Furthermore, addition of nonmetabolizeable glucose analogs had a similar effect on fructose catabolism by the wild-type Z. mobilis CP4, and fructose uptake by Z. mobilis CP4-M2 was shown to be severely inhibited by equimolar amounts of glucose. These results suggest that competition for fructose transport plays an important role in preferential catabolism of glucose from sugar mixtures. Indeed, the apparent K(infm) values for sugar uptake by Z. mobilis CP4 were approximately 200 mM for fructose and 13 mM for glucose. Other experiments supported the conclusion that a single facilitated diffusion transport system, encoded by the glf gene, is solely responsible for the uptake of both glucose and fructose. The results are discussed with regard to the hypothesis that the kinetics of sugar transport and phosphorylation allow the preferential consumption of glucose and accumulation of fructose, making the fructose available for the enzyme glucose-fructose oxidoreductase, which forms sorbitol, an important osmoprotectant for Z. mobilis when growing in the presence of high sugar concentrations.

Molecular genetic characterization of the Escherichia coli gntT gene of GntI, the main system for gluconate metabolism

The Escherichia coli gntT gene was subcloned from the Kohara library, and its expression was characterized. The cloned gntT gene genetically complemented mutant E. coli strains with defects in gluconate transport and directed the formation of a high-affinity gluconate transporter with a measured apparent Km of 6 microM for gluconate. Primer extension analysis indicated two transcriptional start sites for gntT, which are separated by 66 bp and which give rise to what appears on a Northern blot to be a single, gluconate-inducible, 1.42-kb gntT transcript. Thus, it was concluded that gntT is monocistronic and is regulated by two promoters. Both of the promoters have - 10 and -35 sequence elements typical of sigma70 promoters and catabolite gene activator protein binding sites in appropriate locations to exert glucose catabolite repression. In addition, two putative gnt operator sites were identified in the gntT regulatory region. A search revealed the presence of nearly identical palindromic sequences in the regulatory regions of all known gluconate-inducible genes, and these seven putative gnt operators were used to derive a consensus gnt operator sequence. A gntT::lacZ operon fusion was constructed and used to examine gntT expression. The results indicated that gntT is maximally induced by 500 microM gluconate, modestly induced by very low levels of gluconate (4 microM), and partially catabolite repressed by glucose. The results also showed a pronounced peak of gntT expression very early in the logarithmic phase, a pattern of expression similar to that of the Fis protein. Thus, it is concluded that GntT is important for growth on low concentrations of gluconate, for entry into the logarithmic phase, and for cometabolism of gluconate and glucose.

Characterization of a novel transporter family that includes multiple Escherichia coli gluconate transporters and their homologues

The nucleotide sequences of seven Escherichia coli genes that encode members of the gluconate permease (GntP) family have recently become available. These genes include gntP, gntU, gntW, ORf449, dsdX, and ORFo454. The deduced amino acid sequences of all seven E. coli genes are homologous to the gntP gene products from Bacillus subtilis and B. licheniformis as well as two additional gene products from Haemophilus influenzae. These 11 proteins are not demonstrably homologous to members of the major facilitator superfamily or other recognized permease families. Four of the E. coli gluconate transporter genes have been cloned and shown to encode gluconate transporters with apparent affinities ranging from 6 to 212 microM. These studies serve to characterize a novel family of bacterial permeases.

Setting health priorities: community boards accurately reflect the preferences of the community's residents

Setting priorities remains an important part of healthcare planning and program management. Local community input is often sought in government or publicly sponsored programs. Community policy/advisory boards are a common vehicle to represent the community's interests in program decisions and direction. Questions remain whether community boards accurately represent their communities' views. As part of a planning effort within Chicago and Cook County, Illinois, local District Health Councils (DHCs) have been created to provide assistance and leadership in systemization and improvement of the healthcare in communities with the poorest health status in the region. We sought to discover how closely the perceptions of health priorities of DHC members agreed with those of community members. A structured five-point Likert scale questionnaire of 22 of the most common diseases and conditions known to impact health were used for a random digit dialing telephone interview with a sample of 286 households from three under-served communities. The same interview was repeated with all DHC members (n = 80) representing those communities. Sociodemographic profiles and health-related behaviors were also collected. The results of this interview indicate a close and substantial agreement in priorities between community members and DHC members. Psychosocial conditions such as violence and substance abuse were ranked as the highest priorities by both groups. In contrast, sociodemographics and healthcare behavior differed significantly between DHC members and community's residents. This study demonstrates that these community policy/advisory boards can closely reflect the views of the communities they represent. Attention to their differences in sociodemographics and healthcare experiences with the community may strengthen their role even more.

The role of expectations in the perception of health care quality: developing a conceptual model

Proposes a conceptual model of quality which incorporates an expectation framework. The model was prompted by a related empirical study examining effectiveness in a health care setting which highlighted the importance of quality measures in a contracting environment. The model attempts to understand the relationships between perceived service quality and patient expectations, experience and satisfaction. Makes recommendations which are considered to be relevant to NHS policy makers.

Synthesis and preliminary evaluation of (S)-(2-[18F]fluoro-4,5-dihydroxyphenyl)-2-methyl L-alanine, (S)-[18F]-FMEDOPA, a potentially improved imaging agent for the presynaptic dopaminergic nervous system

The synthesis and preliminary rat biodistribution studies of (S)-(2-[18F]fluoro-4,5-dihydroxyphenyl)-2-methyl L-alanine, (S)-[18F]-FMEDOPA, a potentially improved imaging agent for the presynaptic dopaminergic nervous system, are reported. (S)-[18F]-FMEDOPA produces a higher striatum-to-cerebellum (S/C) radioactivity ratio than the currently used PET imaging agent, (S)-[18F]-FDOPA, does at 180 min after administration.

Cloning and expression of the Zymomonas mobilis "production of ethanol" genes in Lactobacillus casei

This study describes the expression of the Zymomonas mobilis genes coding for pyruvate decarboxylase (pdc) and alcohol dehydrogenase (adh) in Lactobacillus casei 686. To promote transcription, the promoter and ribosome binding site (RBS) from the Lactococcus lactis subsp. lactis-derived vector, pMGE36e, were inserted upstream of the pdc gene. The former sequences were positioned such that translation of pdc was coupled to translation of an 81-base pair open reading frame terminating within the pdc initiation site. The recombinant plasmid (pRSG02) was electroporated into L. casei, and transformants were obtained. Northern analysis confirmed the production of a 3. 1-kb transcript corresponding to the predicted size of the PET operon. Western blot analyses revealed that the recombinant strain expressed both enzymes. The recombinant produced more than twice the ethanol produced by the parental L. casei strain.

Evolution of carbohydrate metabolic pathways

Current studies of hyperthermophilic archaea and bacteria, the phylogenetically deepest-rooted and slowest-evolving extant organisms known, are allowing new insights into the nature of presumably ancient metabolic pathways. The apparent common occurrence of modified non-phosphorylated Entner-Doudoroff (ED) pathways among saccharolytic archaea and the absence of the conventional Embden-Meyerhof-Parnas (EMP) mode of glycolysis indicate that the ED pathway is the older route of carbohydrate dissimilation. However, gluconeogenesis via the "reversed" EMP route has been found in archaea. Thus, the EMP pathway was probably an anabolic pathway to begin with; its catabolic role came later, with the evolution of fructose phosphate kinases, using ATP, ADP or pyrophosphate as phosphate donors. Similarly, the presence of reductive reactions of the citric acid cycle in anaerobic archaea and the most deeply rooted bacteria, including autotrophs, indicates that the citric acid cycle was originally a reductive biosynthetic pathway.

BRCA1 testing in families with hereditary breast-ovarian cancer. A prospective study of patient decision making and outcomes

OBJECTIVES

To identify predictors of utilization of breast-ovarian cancer susceptibility (BRCA1 gene) testing and to evaluate outcomes of participation in a testing program.

DESIGN

Prospective cohort study with baseline interview assessment of predictor variables (eg, sociodemographic factors, knowledge about hereditary cancer and genetic testing, perceptions of testing benefits, limitations, and risks). BRCA1 test results were offered after an education and counseling session in a research setting. Outcome variables (including depression, functional health status, and prophylactic surgery plans [follow-up only]) were assessed at baseline and 1-month follow-up interviews.

PARTICIPANTS

Adult male and female members (n=279) of families with BRCA1-linked hereditary breast-ovarian cancer (HBOC).

RESULTS

Of subjects who completed a baseline interview (n=192), 60% requested BRCA1 test results (43% of all study subjects requested results). Requests for results were more frequent for persons with health insurance (odds ration [OR], 3.74; 95% confidence interval [CI], 2.06-6.80); more first-degree relatives affected with breast cancer (OR, 1.59; 95% CI, 1.16-2.16); more knowledge about BRCA1 testing (OR, 1.85; 95% CI, 1.36-2.50); and indicating that test benefits are important (OR, 1.45; 95% CI, 1.13-1.86). At follow-up, noncarriers of BRCA1 mutations showed statistically significant reductions in depressive symptoms and functional impairment compared with carriers and nontested individuals. Individuals identified as mutation carriers did not exhibit increases in depression and functional impairment. Among unaffected women with no prior prophylactic surgery, 17% of carriers (2/12) intended to have mastectomies and 33% (4/12) to have oophorectomies.

CONCLUSIONS

Only a subset of HBOC family members are likely to request BRCA1 testing when available. Rates of test use may be higher in persons of a higher socioeconomic status and those with more relatives affected with breast cancer. For some high-risk individuals who receive test results in a research setting that includes counseling, there may be psychological benefits. More research is needed to assess the generalizability of these results and evaluate the long-term consequences of BRCA1 testing.

Cloning and molecular genetic characterization of the Escherichia coli gntR, gntK, and gntU genes of GntI, the main system for gluconate metabolism

Three genes involved in gluconate metabolism, gntR, gntK, and gntU, which code for a regulatory protein, a gluconate kinase, and a gluconate transporter, respectively, were cloned from Escherichia coli K-12 on the basis of their known locations on the genomic restriction map. The gene order is gntU, gntK, and gntR, which are immediately adjacent to asd at 77.0 min, and all three genes are transcribed in the counterclockwise direction. The gntR product is 331 amino acids long, with a helix-turn-helix motif typical of a regulatory protein. The gntK gene encodes a 175-amino-acid polypeptide that has an ATP-binding motif similar to those found in other sugar kinases. While GntK does not show significant sequence similarity to any known sugar kinases, it is 45% identical to a second putative gluconate kinase from E. coli,gntV. The 445-amino-acid sequence encoded by gntU has a secondary structure typical of membrane-spanning transport proteins and is 37% identical to the gntP product from Bacillus subtilis. Kinetic analysis of GntU indicates an apparent Km for gluconate of 212 microM, indicating that this is a low-affinity transporter. Studies demonstrate that the gntR gene is monocistronic, while the gntU and gntK genes, which are separated by only 3 bp, form an operon. Expression of gntR is essentially constitutive, while expression of gntKU is induced by gluconate and is subject to fourfold glucose catabolite repression. These results confirm that gntK and gntU, together with another gluconate transport gene, gntT, constitute the GntI system for gluconate utilization, under control of the gntR gene product, which is also responsible for induction of the edd and eda genes of the Entner-Doudoroff pathway.

The internist's role in addressing violence. A review of current recommendations and a model for intervention

Approximately 25,000 people die in the United States each year as the result of intentional homicide, and many millions more suffer the physical and emotional consequences of nonfatal interpersonal violence. Violence affects everybody's quality of life. The cost to the health care system is in the billions of dollars annually. Over the past 2 decades epidemiologic studies have defined risk factors for violence, and a number of physicians and medical groups have made recommendations for preventive action. As the largest physician group in the United States, internists have a clear role to play in carrying out the medical responsibility to help prevent violence. Internists should be aware of the signs and symptoms of violence in patients and be prepared to assist victims. To facilitate action against violence, a model for intervention is proposed that involves screening, counseling, and treatment for patients at greatest risk.

Effects of dietary calcium and phosphorus on vitamin D metabolism and calcium absorption in hamster

We studied the following responses to restriction of dietary calcium and phosphorus in the growing hamster: (i) serum concentrations of calcium, inorganic phosphorus, magnesium, and vitamin D metabolites; and (ii) calcium transport by ileum. Diets fed were normal calcium with normal or low phosphorus or low calcium with normal or low phosphorus. We found serum 1 alpha,25-dihydroxycalciferol (1,25-[OH]2D) concentration did not differ significantly among the diet groups. Calcium absorption, measured as serosal/mucosal calcium concentration ratio produced by everted ileal sac, was greater in the low calcium, normal phosphorous group than in all other groups. The other groups did not differ from one another in calcium absorption. Feeding the low calcium, normal phosphorus diet increased inorganic phosphorus and magnesium but decreased calcium concentration in serum in comparison with the three other diets. Both low phosphorus diets were without effect on serum calcium, but the low calcium, low phosphorus diet increased serum inorganic phosphorus and magnesium above that of the normal calcium, low phosphorus diet. Ileal calcium absorption in hamster (i) was independent of serum 1,25-(OH)2D concentration; (ii) increased in response to low dietary calcium if dietary phosphorus was normal; and (iii) was independent of dietary calcium, if dietary phosphorus was low. Despite increased calcium absorption, serum calcium was decreased in the low calcium-normal phosphorus group as compared with all other groups. Feeding low calcium diets increased serum inorganic phosphorus and magnesium as compared with feeding the corresponding normal calcium diets (i.e., independently of whether dietary phosphorus content was normal or low). These studies demonstrate that the interrelationships between calcium absorption and vitamin D and mineral metabolism in hamster differ from other mammals.

The gntP gene of Escherichia coli involved in gluconate uptake

The gntP gene, located between the fim and uxu loci in Escherichia coli K-12, has been cloned and characterized. Nucleotide sequencing of a region encompassing the gntP gene revealed an open reading frame of 447 codons with significant homology to the Bacillus subtilis gluconate permease. Northern (RNA) blotting indicated that the gntP gene was monocistronic and was transcribed as an mRNA with an apparent molecular size of 1.54 kb. The transcriptional start point was determined by primer extension analysis. The gntP gene was found to be under catabolite repression and was not induced by gluconate. Also, expression seemed to be stringently controlled. Several observations indicated that the GntP protein is an inner membrane protein; it contains characteristic membrane-spanning regions and was isolated predominantly from the inner-membrane fraction of fractionated host cells. A topology analysis predicted a protein with 14 membrane-spanning segments. The inability of a mutant strain to grow on gluconate minimal medium could be relieved by introduction of a plasmid encoding the gntP gene. Finally, the kinetics of GntP-mediated gluconate uptake were investigated, indicating an apparent Km for gluconate of 25 microM.

Single-run separation and detection of multiple metabolic intermediates by anion-exchange high-performance liquid chromatography and application to cell pool extracts prepared from Escherichia coli

A method is described for analysis of the intracellular concentrations of metabolic intermediates of the Embden-Meyerhof-Parnas pathway, the Entner-Doudoroff pathway, the pentose phosphate pathway, and the tricarboxylic acid cycle in cell pool extracts of Escherichia coli. A single anion-exchange HPLC run of 40 min allowed resolution of 27 anionic metabolite standards. Detection limits of 0.1 nmol per injection were achieved by use of a conductivity detector equipped with an anion self-regenerating suppressor and a uv detector. A boiling water extraction procedure was used to prepare cell pool extracts. Cochromatography of cell pool extracts and metabolite standards was used to confirm the identities of metabolites in the cell pool. As many as 16 metabolites could be detected and quantified in the cell pool extracts by using the described HPLC method. An analysis of metabolite concentrations in E. coli showed the dynamics of glucose metabolism during a 2-min transition from starvation to steady-state metabolism following addition of glucose. The ease and power of this method suggests general utility for in vivo metabolite analysis in a variety of experimental systems.

Violence victims' perception of functioning and well-being: a survey from an urban public hospital walk-in clinic

This study assessed the health perceptions of self-reported violence victims in an urban minority population attending a walk-in clinic by using an anonymous, 1-week, cross-sectional survey. The Medical Outcome Study Short-Form (MOS SF-20) was used to assess functioning/well being, including the dimensions of physical functioning, role functioning, social functioning, mental health, health perceptions, and pain. Health perception main scores were calculated for each of the six health dimensions in the following four groups: patient-victims, patient-nonvictims, visitor-victims, and visitor-nonvictims. Odds ratios (OR) were calculated to assess the association of violence victimization and functioning/well-being. The mean scores of health status were consistently better among nonvictims for all of the six health concepts measured; patients who were victims showed lower mean scores than nonvictim patients. A similar pattern also was found in visitors' health status scores when victims were compared to nonvictims. The strongest association was found between violence victimization and mental health, and the least association was between the pain score and violence victimization. This study showed a substantial association between poor health and violence victimization in the patient population studied. Intervention is needed to prevent and decrease violence in order to minimize the impact of violence on the health of victims.

Characterization of the Zymomonas mobilis glucose facilitator gene product (glf) in recombinant Escherichia coli: examination of transport mechanism, kinetics and the role of glucokinase in glucose transport

Zymomonas mobilis is known to transport glucose by a facilitated diffusion process. A putative glucose facilitator gene (glf), closely related to a large family of glucose transporters, is located in a cluster of genes that code for enzymes of glucose metabolism. The Z. mobilis glf gene is able to complement glucose transport in an Escherichia coli strain that is defective in native glucose transport and glucokinase. In this study, the recombinant E. coli was shown to be capable of influx counterflow when preloaded with glucose and had an apparent Km for glucose of approximately 1.1-2.9 mM, consistent with the function of Glf as a low-affinity glucose facilitator. The ability of glucokinase mutants expressing glf to transport glucose made it clear that glucokinase activity was not required for Glf-dependent glucose transport. The possibility that glucokinase can interact with Glf to improve the affinity for glucose was not supported since expression of the Z. mobilis glucokinase gene, in addition to glf, did not affect the Km of Glf for glucose in recombinant E. coli. The inability of various sugars to compete with glucose during glucose transport by recombinant E. coli expressing glf indicated that Glf is specific for glucose. While the results of fructose transport assays did not completely rule out the possibility of very low affinity for fructose, the apparent specificity of Glf for glucose makes it possible that Z. mobilis utilizes a different transporter(s) for fructose.

Are primary care residents adequately prepared to care for women of reproductive age?

A 1991 study of 115 internal medicine and 28 family practice residents at a large inner-city public hospital finds that both groups would perform poorly in providing preconception counseling to women of reproductive age. More than 40% of residents failed to indicate that they would provide a healthy woman with information on rubella immunization and family planning or counseling on sexually transmitted diseases and safer sex. When counseling a diabetic woman seeking pregnancy, 74% would not have discussed congenital anomalies with her and 45% would not have considered discontinuing oral hypoglycemics if she became pregnant. Furthermore, 58% would have neglected to review or change hypertension medications in a newly diagnosed pregnant woman. Although both internal medicine and family practice residents had positive attitudes toward offering preconception care, family practice residents had significantly higher attitude scores. No clear improvement was found in patient management, attitude or knowledge scores as residents progressed from their first to their third year of training.

Breast cancer and importance of zygosity determination in triplet sisters

This study is the first to examine the genetic risk in a breast cancer-prone family wherein two of three triplet sisters and their mother manifested breast cancer. The unaffected triplet, the proband, was found to be monozygotic with her deceased sister through DNA testing of tumor blocks and dizygotic to her living affected sister. Genetic counseling implications are discussed.

Prevalence of violence victimization among patients seen in an urban public hospital walk-in clinic

OBJECTIVES

To study the prevalence of serious physical interpersonal violence and to identify the types of perpetrators, the frequency of occurrence, the time since the violence occurred, the risk profiles, and other factors related to victimization.

METHODS

One-week survey of all consecutively registered patients and their visitors in an urban public hospital adult walk-in clinic, using an anonymous self-administered questionnaire.

RESULTS

Of the 1,504 patients, 1,041 (69.2%) completed the questionnaire. The reported experience of serious physical violence victimization for the whole study population, both patients (n = 1,041) and visitors (n = 155), was 47.9% (573/1,196). A violence victim was more likely to be male [odds ratio (OR) = 1.41, 95% confidence interval (CI): 1.11, 1.78], African-American (OR = 1.27, 95% CI: 0.98, 1.63), aged 45 years or younger (OR = 1.55, 95% CI: 1.19, 2.03), and single (OR = 1.47, 95% CI: 1.16, 1.86). Alcohol use and drug use were clearly associated with violence victimization, with prevalence ORs of 2.26 (95% CI: 1.80, 2.85) for alcohol and 3.68 (95% CI: 2.66, 5.09) for drugs.

CONCLUSION

A history of serious physical violence victimization is common in inner-city hospital walk-in clinic patients. Walk-in clinics in urban areas of high violence, therefore, may prove to be important places for intervention and prevention of violence.

Psychological aspects of monitoring high risk women for breast cancer

BACKGROUND

There is a paucity of knowledge pertaining to the attitudes, feelings, and emotions of women who are at increased familial risk for breast cancer and how these concerns will affect their surveillance behavior. A review of the literature shows an unevenness in the conclusions about these matters, with some reports indicating that anxiety aroused in the familial cancer setting may abet surveillance behavior, whereas other data indicates a negative effect.

METHODS

The authors reported anecdotal accounts of such behavior in women from hereditary breast and hereditary breast-ovarian cancer prone families.

RESULTS

Although these responses of fear, anxiety, and apprehension about cancer risk are not unique to this hereditary cohort, they nevertheless must have been tempered by often life-long exposure of cancer occurrences that may have decimated their families.

CONCLUSIONS

All accounts agree with the need to devote more research to the special needs--psychological, social, insurance, and general public health measures--of these high risk women.

Familial aggregation of carcinoma of the endometrium

OBJECTIVE

Our purpose was to describe histologically verified endometrial carcinoma and other cancer types manifested through three generations in a pedigree, where these findings do not fit any classic hereditary cancer syndrome.

STUDY DESIGN

Our family study protocol used detailed patient interviews whenever possible and questionnaires with permission forms that, when signed, enabled retrieval of pertinent medical-genetic and pathologic study documents.

RESULTS

Endometrial carcinoma was histologically verified in five women through three consecutive generations. The triad of obesity, hypertension, and diabetes mellitus was not observed. Primary carcinomas of both the endometrium and ovary and endometrium and lymphoma were documented in two relatives in the direct genetic lineage of the pedigree.

CONCLUSION

An aggregation of endometrial carcinoma in families, even when classic hereditary cancer syndrome identification is lacking, nevertheless merits surveillance and management strategies targeted to putative high-risk family members.

Attitudes, knowledge, and skills of internal medicine residents regarding pre-conception care

BACKGROUND

A questionnaire was designed based on current recommendations for pre-conception care and care of women at the time of diagnosis of pregnancy to evaluate internal medicine residents' attitudes, knowledge, and clinical management skills in the pre-conception care of healthy women and women who have chronic diseases during their reproductive years.

METHOD

In early 1991, a self-administered questionnaire was distributed to 104 internal medicine residents at Cook County Hospital, a large, inner-city public hospital. Statistical analysis included the use of chi-square comparison, Pearson correlation, and Student's t-test.

RESULTS

Seventy-nine of the residents completed questionnaires. Their levels of knowledge and management skills regarding pre-conception care were relatively low compared with standard recommendations. The residents' attitudes, however, were favorable toward the importance of the topic. Residency training did not appear to improve the residents' management skills, as there was no significant difference in skills among the first-, second-, and third-year residents.

CONCLUSION

That the residents' levels of knowledge and management skills were low (despite their favorable attitudes) suggests that the current curriculum for primary care training in internal medicine needs to be revised to improve the readiness of residents to take care of women of reproductive age.

Reconstruction of glucose uptake and phosphorylation in a glucose-negative mutant of Escherichia coli by using Zymomonas mobilis genes encoding the glucose facilitator protein and glucokinase

Expression of the Zymomonas mobilis glf (glucose facilitator protein) and glk (glucokinase) genes in Escherichia coli ZSC113 (glucose negative) provided a new functional pathway for glucose uptake and phosphorylation. Both genes were essential for the restoration of growth in glucose minimal medium and for acid production on glucose-MacConkey agar plates.

Hereditary breast cancer and family cancer syndromes

Hereditary breast cancer (HBC) shows extant clinical and genetic heterogeneity. Clinically one finds the onset of breast cancer at an early age, an excess of bilaterality, and patterns of multiple primary cancer such as combinations of breast and ovarian carcinoma in the hereditary breast-ovarian cancer (HBOC) syndrome. In addition to HBOC, one sees a variety of putative breast cancer-prone genotypes inclusive of hereditary site-specific breast cancer, and the Li-Fraumeni (SBLA) syndrome that is characterized by cancers involving all three germinal layers including sarcomas, brain tumors, leukemia, lymphoma, and adrenal cortical carcinoma in addition to often markedly early-onset breast cancer. Breast cancer is also associated with autosomal dominantly inherited Cowden's disease and autosomal recessively inherited ataxia-telangiectasia. Examples of pedigrees depicting clinical examples of these several HBC syndromes are presented in order to describe HBC's heterogeneity. The recent identification of the BRCA1 gene in early-onset hereditary site-specific breast cancer and the HBOC syndrome has led to new challenges for the genetic counselor. We review genetic counseling, which embraces surveillance and management recommendations that are responsive to the natural history of HBC and address the concept for future development of centers of expertise for HBC in the interest of improving cancer control.