Sequence and organization of the human mitochondrial genome

The complete sequence of the 16,569-base pair human mitochondrial genome is presented. The genes for the 12S and 16S rRNAs, 22 tRNAs, cytochrome c oxidase subunits I, II and III, ATPase subunit 6, cytochrome b and eight other predicted protein coding genes have been located. The sequence shows extreme economy in that the genes have none or only a few noncoding bases between them, and in many cases the termination codons are not coded in the DNA but are created post-transcriptionally by polyadenylation of the mRNAs.

Leptin levels reflect body lipid content in mice: evidence for diet-induced resistance to leptin action

The regulation of body weight and composition involves input from genes and the environment, demonstrated, for example, by the variable susceptibility of inbred strains of mice to obesity when offered a high-fat diet. The identification of the gene responsible for obesity in the ob/ob mouse provides a new approach to defining links between diet and genetics in the regulation of body weight. The ob gene protein product, leptin, is an adipocyte-derived circulating protein. Administration of recombinant leptin reduces food intake and increases energy expenditure in ob/ob mice, suggesting that it signals to the brain the magnitude of fat stores. Information on the regulation of this protein is limited. In several rodent models of obesity including db/db, fa/fa, yellow (Ay/a) VMH-lesioned, and those induced by gold thioglucose, monosodium glutamate, and transgenic ablation of brown adipose tissue, leptin mRNA expression and the level of circulating leptin are increased, suggesting resistance to one or more of its actions. We have assessed the impact of increased dietary fat on circulating leptin levels in normal FVB mice and FVB mice with transgene-induced ablation of brown adipose tissue. We find that high-fat diet evokes a sustained increase in circulating leptin in both normal and transgenic mice, with leptin levels accurately reflecting the amount of body lipid across a broad range of body fat. However, despite increased leptin levels, animals fed a high-fat diet became obese without decreasing their caloric intake, suggesting that a high content of dietary fat changes the 'set point' for body weight, at least in part by limiting the action of leptin.

Reanalysis and results after 12 years of follow-up in a randomized clinical trial comparing total mastectomy with lumpectomy with or without irradiation in the treatment of breast cancer

BACKGROUND

Previous findings from a clinical trial (Protocol B-06) conducted by the National Surgical Adjuvant Breast and Bowel Project (NSABP) indicated the worth of lumpectomy and breast irradiation for treating breast cancer. After the discovery by NSABP staff members of falsified information on patients enrolled in the study by St. Luc Hospital in Montreal, separate audits were conducted at St. Luc Hospital and other participating institutions. We report the results of both audits and update the study findings through an average of 12 years of follow-up.

METHODS

Patients with either negative or positive axillary nodes and tumors 4 cm or less in diameter were randomly assigned to one of three treatments: total mastectomy, lumpectomy followed by breast irradiation, or lumpectomy without irradiation. Three cohorts of patients were analyzed. The first cohort included all 2105 randomized patients, who were analyzed according to the intention-to-treat principle. The second cohort consisted of 1851 eligible patients in the first cohort with known nodal status who agreed to be followed and who accepted their assigned therapy (among those excluded were 6 patients from St. Luc Hospital who were declared ineligible because of falsified biopsy dates). The third cohort consisted of the patients in the second cohort minus the 322 eligible patients from St. Luc Hospital (total, 1529 patients).

RESULTS

Regardless of the cohort, no significant differences were found in overall survival, disease-free survival, or survival free of disease at distant sites between the patients who underwent total mastectomy and those treated by lumpectomy alone or by lumpectomy plus breast irradiation. After 12 years of follow-up, the cumulative incidence of a recurrence of tumor in the ipsilateral breast was 35 percent in the group treated with lumpectomy alone and 10 percent in the group treated with lumpectomy and breast irradiation (P < 0.001).

CONCLUSIONS

Our findings continue to indicate that lumpectomy followed by breast irradiation is appropriate therapy for women with either negative or positive axillary nodes and breast tumors 4 cm or less in diameter.

Disruption of two novel genes by a translocation co-segregating with schizophrenia

A balanced (1;11)(q42.1;q14.3) translocation segregates with schizophrenia and related psychiatric disorders in a large Scottish family (maximum LOD = 6.0). We hypothesize that the translocation is the causative event and that it directly disrupts gene function. We previously reported a dearth of genes in the breakpoint region of chromosome 11 and it is therefore unlikely that the expression of any genes on this chromosome has been affected by the translocation. By contrast, the corresponding region on chromosome 1 is gene dense and, not one, but two novel genes are directly disrupted by the translocation. These genes have been provisionally named Disrupted-In-Schizophrenia 1 and 2 ( DISC1 and DISC2 ). DISC1 encodes a large protein with no significant sequence homology to other known proteins. It is predicted to consist of a globular N-terminal domain(s) and helical C-terminal domain which has the potential to form a coiled-coil by interaction with another, as yet, unidentified protein(s). Similar structures are thought to be present in a variety of unrelated proteins that are known to function in the nervous system. The putative structure of the protein encoded by DISC1 is therefore compatible with a role in the nervous system. DISC2 apparently specifies a non-coding RNA molecule that is antisense to DISC1, an arrangement that has been observed at other loci where it is thought that the antisense RNA is involved in regulating expression of the sense gene. Altogether, these observations indicate that DISC1 and DISC2 should be considered formal candidate genes for susceptibility to psychiatric illness.

Glomeruli and blood pressure. Less of one, more the other?

A primary role for the kidney in the initiation and maintenance of hypertension has long been recognized, but the pathogenetic interactions among renal hemodynamics, hormonal and hereditary factors, and dietary sodium intake remain enigmatic. Reduction in filtration surface area, whether acquired in the course of intrinsic renal disease or after surgical renal ablation, leads to systemic hypertension as well as to progressive renal insufficiency, sequellae made even more severe by dietary sodium excess. Moreover, hypertension and progressive renal disease eventuate in some individuals born with a solitary kidney, as well as in those with more severe degrees of dysgenesis (ie, oligomeganephronia). Hypertension is also commonly observed in certain inbred rat strains in which filtration surface area is congenitally deficient. Based on these and other lines of evidence reviewed herein, we postulate that a renal abnormality that contributes to essential hypertension in the general population is a reduced number of nephrons. The consequences of this abnormality are limitations in the ability to excrete sodium and thus, salt-sensitive hypertension. Finally, congenital variability in filtration surface area may explain why only some, but not all, patients exposed to potentially injurious renal stimuli eventually manifest chronic nephropathy. This may also account for the susceptibility of subsets of Type I and Type II diabetics to develop overt glomerulopathy.

Prevention of diabetic glomerulopathy by pharmacological amelioration of glomerular capillary hypertension

Two groups of adult male Munich-Wistar rats and a third group of nondiabetic age-matched and weight-matched normal control rats underwent micropuncture study 1 mo, and morphologic studies 14 mo, after induction of streptozotocin diabetes or sham treatment. All animals were fed standard rat chow. Diabetic rats received daily ultralente insulin to maintain stable moderate hyperglycemia (approximately 350 mg/dl). In addition, one group of diabetic rats was treated with the angiotensin I converting enzyme inhibitor, enalapril, 15 mg/liter of drinking water. Average kidney weight, whole kidney and single-nephron glomerular filtration rate, and glomerular plasma flow rate were elevated to similar values in both groups of diabetic rats, relative to normal control rats. Non-enalapril-treated diabetic rats exhibited significant elevations in mean glomerular capillary hydraulic pressure and transcapillary hydraulic pressure gradient, compared with the other groups studied, and only this group eventually developed marked and progressive albuminuria. Likewise, histological examination of the kidneys at 14 mo disclosed a high incidence of glomerular structural abnormalities only in non-enalapril-treated diabetic rats. These findings indicate that prevention of glomerular capillary hypertension in rats with diabetes mellitus effectively protects against the subsequent development of glomerular structural injury and proteinuria. This protection is afforded despite pronounced hyperglycemia and elevated levels of glucosylated hemoglobin, further supporting our view that hemodynamic rather than metabolic factors predominate in the pathogenesis of diabetic glomerulopathy.

Therapeutic advantage of converting enzyme inhibitors in arresting progressive renal disease associated with systemic hypertension in the rat

Micropuncture and morphologic studies were performed in six groups of male Munich-Wistar rats after removal of the right kidney and segmental infarction of two-thirds of the left kidney. Groups 1 and 4 received no specific therapy. Groups 2 and 5 were treated with the angiotensin I-converting enzyme inhibitor, enalapril, 50 mg/liter, in the drinking water. Groups 3 and 6 were treated with reserpine (5 mg/liter), hydralazine (80 mg/liter), and hydrochlorothiazide (25 mg/liter). All rats were fed standard chow. Groups 1-3 underwent micropuncture study 4 wk after renal ablation. Untreated group 1 rats exhibited systemic hypertension and elevation of the single nephron glomerular filtration rate (SNGFR) due to high average values for the mean glomerular transcapillary hydraulic pressure gradient (delta P) and glomerular plasma flow rate (QA). In group 2 rats, treatment with enalapril prevented systemic hypertension and maintained delta P at near-normal levels without significant reduction in SNGFR and QA. In contrast, triple drug therapy normalized systemic hypertension, but failed to lower delta P in group 3 rats. Groups 4-6 were followed for 12 wk after renal ablation. Untreated group 4 rats demonstrated continuous systemic hypertension, progressive proteinuria, and glomerular structural lesions, including mesangial expansion and frequent areas of segmental sclerosis. In group 5 rats, treatment with enalapril maintained systemic blood pressure at normal levels over the 12-wk period and dramatically limited the development of proteinuria and glomerular lesions. Despite equivalent systemic blood pressure control in group 6 rats, failure of triple drug therapy to control glomerular hypertension was associated with progressive proteinuria and glomerular lesions comparable to those seen in untreated group 4 rats. Thus, unless glomerular capillary hypertension is corrected, control of systemic blood pressure is insufficient to prevent progressive renal injury in rats with reduced renal mass.

A randomized trial comparing ticlopidine hydrochloride with aspirin for the prevention of stroke in high-risk patients. Ticlopidine Aspirin Stroke Study Group

We report the results of the Ticlopidine Aspirin Stroke Study, a blinded trial at 56 North American centers that compared the effects of ticlopidine hydrochloride (500 mg daily) with those of aspirin (1300 mg daily) on the risk of stroke or death. The medications were randomly assigned to 3069 patients with recent transient or mild persistent focal cerebral or retinal ischemia. Follow-up lasted for two to six years. The three-year event rate for nonfatal stroke or death from any cause was 17 percent for ticlopidine and 19 percent for aspirin--a 12 percent risk reduction (95 percent confidence interval, -2 to 26 percent) with ticlopidine (P = 0.048 for cumulative Kaplan-Meier estimates). The rates of fatal and nonfatal stroke at three years were 10 percent for ticlopidine and 13 percent for aspirin--a 21 percent risk reduction (95 percent confidence interval, 4 to 38 percent) with ticlopidine (P = 0.024 for cumulative Kaplan-Meier estimates). Ticlopidine was more effective than aspirin in both sexes. The adverse effects of aspirin included diarrhea (10 percent), rash (5.5 percent), peptic ulceration (3 percent), gastritis (2 percent), and gastrointestinal bleeding (1 percent). With ticlopidine, diarrhea (20 percent), skin rash (14 percent), and severe but reversible neutropenia (less than 1 percent) were noted. The mean increase in total cholesterol level was 9 percent with ticlopidine and 2 percent with aspirin (P less than 0.01). The ratios of high-density lipoprotein and low-density lipoprotein to total cholesterol were similar in both treatment groups. We conclude that ticlopidine was somewhat more effective than aspirin in preventing strokes in this population, although the risks of side effects were greater.

Control of glomerular hypertension limits glomerular injury in rats with reduced renal mass

Micropuncture and morphologic studies were performed in four groups of male Munich-Wistar rats after removal of the right kidney and segmental infarction of two-thirds of the left kidney. Groups 1 and 3 received no specific therapy. Groups 2 and 4 were treated with the angiotensin I converting enzyme inhibitor, enalapril, 50 mg/liter of which was put in their drinking water. All rats were fed standard chow. Groups 1 and 2 underwent micropuncture study 4 wk after renal ablation. Untreated group 1 rats exhibited systemic hypertension and elevation of the single nephron glomerular filtration rate (SNGFR) due to high average values for the mean glomerular transcapillary hydraulic pressure difference and glomerular plasma flow rate. In group 2 rats, treatment with enalapril prevented systemic hypertension and maintained the mean glomerular transcapillary hydraulic pressure gradient at near-normal levels without significantly compromising SNGFR and the glomerular capillary plasma flow rate, as compared with untreated group 1 rats. Groups 3 and 4 were studied 8 wk after renal ablation. Untreated group 3 rats demonstrated persistent systemic hypertension, progressive proteinuria, and glomerular structural lesions, including mesangial expansion and segmental sclerosis. In group 4 rats, treatment with enalapril maintained systemic blood pressure at normal levels over the 8-wk period and significantly limited the development of proteinuria and glomerular lesions. These studies suggest that control of glomerular hypertension effectively limits glomerular injury in rats with renal ablation, and further support the view that glomerular hemodynamic changes mediate progressive renal injury when nephron number is reduced.

Validation studies for models projecting the risk of invasive and total breast cancer incidence

BACKGROUND

In 1989, Gail and colleagues developed a model for estimating the risk of breast cancer in women participating in a program of annual mammographic screening (designated herein as model 1). A modification of this model to project the absolute risk of developing only invasive breast cancer is referred to herein as model 2. We assessed the validity of both models by employing data from women enrolled in the Breast Cancer Prevention Trial.

METHODS

We used data from 5969 white women who were at least 35 years of age and without a history of breast cancer. These women were in the placebo arm of the trial and were screened annually. The average follow-up period was 48.4 months. We compared the observed number of breast cancers with the predicted numbers from the models.

RESULTS

In terms of absolute risk, the ratios of total expected to observed numbers of cancers (95% confidence intervals [CIs]) were 0.84 (0. 73-0.97) for model 1 and 1.03 (0.88-1.21) for model 2, respectively. Within the age groups of 49 years or less, 50-59 years, and 60 years or more, the ratios of expected to observed numbers of breast cancers (95% CIs) for model 1 were 0.91 (0.73-1.14), 0.96 (0.73-1. 28), and 0.66 (0.52-0.86), respectively. Thus, model 1 underestimated breast cancer risk in women more than 59 years of age. For model 2, the risk ratios (95% CIs) were 0.93 (0.72-1.22), 1.13 (0.83-1.55), and 1.05 (0.80-1.41), respectively. Both models exhibited a tendency to overestimate risk for women classified in the higher quintiles of predicted 5-year risk and to underestimate risk for those in the lower quintiles of the same.

CONCLUSION

Despite some limitations, these methods provide useful information on breast cancer risk for women who plan to participate in an annual mammographic screening program.

Significance of ipsilateral breast tumour recurrence after lumpectomy

Breast cancer treatment trials from the US National Surgical Adjuvant Breast and Bowel Project have established breast-conserving operations as a replacement for radical mastectomy (NSABP B-04), and have shown that in terms of survival free from distant disease there was no significant difference between lumpectomy, lumpectomy plus breast irradiation, and total mastectomy (NSABP B-06). 9-year follow-up data from B-06 are used here to address the issue of ipsilateral breast tumour recurrence (IBTR) and the development of distant disease, a question with important clinical and biological implications. A Cox regression model on fixed co-variates (ie, features such as tumour type or size present at surgery and not subsequently alterable) and on IBTR, which is time dependent and not fixed, revealed that the risk of distant disease was 3.41 times greater after adjustment for co-variates in patients in whom an IBTR developed. IBTR proved to be a powerful independent predictor of distant disease. However, it is a marker of risk for, not a cause of, distant metastasis. While mastectomy or breast irradiation following lumpectomy prevent expression of the marker they do not lower the risk of distant disease. These findings further justify the use of lumpectomy.

Is schizophrenia due to excessive synaptic pruning in the prefrontal cortex? The Feinberg hypothesis revisited

Several lines of evidence support the notion that a substantial reorganization of cortical connections, involving a programmed synaptic pruning, takes place during adolescence in humans. A review of neurobiological abnormalities in schizophrenia indicates that the neurobiological parameters that undergo peripubertal regressive changes may be abnormal in this disorder. An excessive pruning of the prefrontal corticocortical, and corticosubcortical synapses, perhaps involving the excitatory glutamatergic inputs to pyramidal neurons, may underlie schizophrenia. A reciprocal failure of pruning in certain subcortical structures, such as lenticular nuclei, may also occur. Several developmental trajectories, related to early brain insults as well as genetic factors affecting postnatal neurodevelopment, could lead to the illness. These models would have heuristic value and may be consistent with several known facts of the schizophrenic illness, such as its onset in adolescence and the gender differences in its onset and natural course. The relationship between these models and other etiological models of schizophrenia are summarized and approaches to test relevant hypotheses are discussed.

Genetic Diversity and Protective Efficacy of the RTS,S/AS01 Malaria Vaccine

BACKGROUND

The RTS,S/AS01 vaccine targets the circumsporozoite protein of Plasmodium falciparum and has partial protective efficacy against clinical and severe malaria disease in infants and children. We investigated whether the vaccine efficacy was specific to certain parasite genotypes at the circumsporozoite protein locus.

METHODS

We used polymerase chain reaction-based next-generation sequencing of DNA extracted from samples from 4985 participants to survey circumsporozoite protein polymorphisms. We evaluated the effect that polymorphic positions and haplotypic regions within the circumsporozoite protein had on vaccine efficacy against first episodes of clinical malaria within 1 year after vaccination.

RESULTS

In the per-protocol group of 4577 RTS,S/AS01-vaccinated participants and 2335 control-vaccinated participants who were 5 to 17 months of age, the 1-year cumulative vaccine efficacy was 50.3% (95% confidence interval [CI], 34.6 to 62.3) against clinical malaria in which parasites matched the vaccine in the entire circumsporozoite protein C-terminal (139 infections), as compared with 33.4% (95% CI, 29.3 to 37.2) against mismatched malaria (1951 infections) (P=0.04 for differential vaccine efficacy). The vaccine efficacy based on the hazard ratio was 62.7% (95% CI, 51.6 to 71.3) against matched infections versus 54.2% (95% CI, 49.9 to 58.1) against mismatched infections (P=0.06). In the group of infants 6 to 12 weeks of age, there was no evidence of differential allele-specific vaccine efficacy.

CONCLUSIONS

These results suggest that among children 5 to 17 months of age, the RTS,S vaccine has greater activity against malaria parasites with the matched circumsporozoite protein allele than against mismatched malaria. The overall vaccine efficacy in this age category will depend on the proportion of matched alleles in the local parasite population; in this trial, less than 10% of parasites had matched alleles. (Funded by the National Institutes of Health and others.).

Complete mitochondrial genome sequences of two extinct moas clarify ratite evolution

The origin of the ratites, large flightless birds from the Southern Hemisphere, along with their flighted sister taxa, the South American tinamous, is central to understanding the role of plate tectonics in the distributions of modern birds and mammals. Defining the dates of ratite divergences is also critical for determining the age of modern avian orders. To resolve the ratite phylogeny and provide biogeographical data to examine these issues, we have here determined the first complete mitochondrial genome sequences of any extinct taxa--two New Zealand moa genera--along with a 1,000-base-pair sequence from an extinct Madagascan elephant-bird. For comparative data, we also generated 12 kilobases of contiguous sequence from the kiwi, cassowary, emu and two tinamou genera. This large dataset allows statistically precise estimates of molecular divergence dates and these support a Late Cretaceous vicariant speciation of ratite taxa, followed by the subsequent dispersal of the kiwi to New Zealand. This first molecular view of the break-up of Gondwana provides a new temporal framework for speciation events within other Gondwanan biota and can be used to evaluate competing biogeographical hypotheses.

Impaired development of Th2 cells in IL-13-deficient mice

We report that Th2 cell cultures generated using T cells or splenocytes from IL-13-deficient mice produce significantly reduced levels of IL-4, IL-5, and IL-10 compared with wild-type. In contrast, IL-4 and IL-5 production by mast cells stimulated in vitro with PMA, ionomycin, or IgE cross-linking are unaffected. In vitro Th2 cell differentiation cannot be rescued by the addition of exogenous factors, but in vivo antigen challenge and administration of IL-13 can increase Th2-like cytokine responses as can infection with the parasitic nematode Nippostrongylus brasiliensis. IL-13-deficient mice also have lower basal levels of serum IgE and biased antigen-specific immunoglobulin responses. Thus, IL-13 is an important regulator of Th2 commitment and may therefore play a central role in atopy and infectious diseases.

Shotgun DNA sequencing using cloned DNase I-generated fragments

A method for DNA sequencing has been developed that utilises libraries of cloned randomly-fragmented DNA. The DNA to be sequenced is first subjected to limit attach by a non-specific endonuclease (DNase I in the presence of Mn++), fractionated by size and cloned in a single-stranded phage vector. Clones are then picked at random and used to provide a template for sequencing by the dideoxynucleotide chain termination method. This technique was used to sequence completely a 4257 bp EcoRI fragment of bovine mitochondrial DNA. The cloned fragments were evenly distributed with respect to the EcoRI fragment, and completion of the entire sequence required the construction of only a single library. In general, once a clone library has been prepared, the speed of this approach (greater than 1000 nucleotides of randomly selected sequence per day) is limited mainly by the rate at which the data can be processed. Because the clones are selected randomly, however, the average amount of new sequence information per clone is substantially diminished as the sequence near completion.

Chronic stress in elderly carers of dementia patients and antibody response to influenza vaccination

BACKGROUND

There are many reports of psychological morbidity in spousal carers of patients with dementia. The consequences of this increased stress on the immune system are unclear. We investigated whether antibody responses to influenza vaccination differed between carers and a control group, and the relation of the antibody response to the hypothalamic-pituitary-adrenal (HPA) axis.

METHODS

50 spousal carers of dementia patients, median age 73 years (IQR 66-77), and 67 controls (68 years [66-71]) of similar socioeconomic status were enrolled. Anxiety and depression were measured by the Savage Aged Personality Screening Scale and stress by the Global Measure of Perceived Stress scale. Principal-component analysis was used to yield a summary score of emotional distress from these two scales. Salivary cortisol concentrations were measured over a single day at three times (0800-1000, 1100-1300, and 2000-2200). Participants received a trivalent influenza vaccine and IgG antibody titres to each strain were measured on days 0, 7, 14, and 28.

FINDINGS

Mean scores of emotional distress were significantly higher in carers at each time point than in controls (all p<0.0003). Mean (SD) salivary cortisol concentrations, calculated as area under the curve (AUC), were higher in carers than controls at all three assessments (6 months 16.0 [8.0] vs 11.2 [4.4], p=0.0001; respectively). Eight (16%) of 50 carers and 26 (39%) of 67 controls had a four-fold increase in at least one of the IgG titres (p=0.007). There was an inverse relation between AUC cortisol and IgG antibody titre to the Nanchang strain that was significant on day 14 (r=-0.216, p=0.039).

INTERPRETATION

Elderly carers of spouses with dementia have increased activation of the hypothalamic-pituitary-adrenal axis and a poor antibody response to influenza vaccine. Carers may be more vulnerable to infectious disease than the population of a similar age.

Lactate provocation of panic attacks. I. Clinical and behavioral findings

To assess the pharmacologic and phenomenologic comparability of lactate-induced and naturally occurring panic attacks, patients meeting DSM-III criteria for panic disorder or agoraphobia with panic attacks were infused with 0.5M racemic sodium lactate before and after successful drug treatment. Lactate-induced and naturally occurring panic attacks were symptomatically similar. Following treatment, the patients' response to lactate did not differ from that of normal controls, whereas the pretreatment panic rate was much higher. These data suggest that lactate acts, by as yet unidentified mechanisms, to trigger the same panic attacks as occur spontaneously in vulnerable persons.

Cell migration from the ganglionic eminences is required for the development of hippocampal GABAergic interneurons

GABAergic interneurons have major roles in hippocampal function and dysfunction. Here we provide evidence that, in mice, virtually all of these cells originate from progenitors in the basal telencephalon. Immature interneurons tangentially migrate from the basal telencephalon through the neocortex to take up their final positions in the hippocampus. Disrupting differentiation in the embryonic basal telencephalon (lateral and medial ganglionic eminences) through loss of Dlx1/2 homeobox function blocks the migration of virtually all GABAergic interneurons to the hippocampus. On the other hand, disrupting specification of the medial ganglionic eminence through loss of Nkx2.1 homeobox function depletes the hippocampus of a distinct subset of hippocampal interneurons. Loss of hippocampal interneurons does not appear to have major effects on the early development of hippocampal projection neurons nor on the pathfinding of afferrent tracts.

An olfactory sensory map develops in the absence of normal projection neurons or GABAergic interneurons

Olfactory sensory neurons expressing a given odorant receptor project to two topographically fixed glomeruli in the olfactory bulb. We have examined the contribution of different cell types in the olfactory bulb to the establishment of this topographic map. Mice with a homozygous deficiency in Tbr-1 lack most projection neurons, whereas mice with a homozygous deficiency in Dlx-1 and Dlx-2 lack most GABAergic interneurons. Mice bearing a P2-IRES-tau-lacZ allele and deficient in either Tbr-1 or Dlx-1/Dlx-2 reveal the convergence of axons to one medial and one lateral site at positions analogous to those observed in wild-type mice. These observations suggest that the establishment of a topographic map is not dependent upon cues provided by, or synapse formation with, the major neuronal cell types in the olfactory bulb.

Differential origins of neocortical projection and local circuit neurons: role of Dlx genes in neocortical interneuronogenesis

Herein we review the evidence that neocortical projection neurons and interneurons are derived from distinct regions within the telencephalon. While neocortical projection neurons are derived from the ventricular zone of the neocortex, neocortical interneurons appear to be derived from the germinal zone of the basal ganglia. These interneurons follow a tangential migratory pathway from the ganglionic eminences to the cortex. Interneurons of the olfactory bulb follow a distinct tangential migration from the basal ganglia. The Dlx homeobox genes, which are essential for basal ganglia differentiation, are also required for the development of neocortical and olfactory bulb interneurons. Furthermore, evidence is presented that retroviral-mediated expression of DLX2 in neocortical cells can induce GABAergic interneuron differentiation.

Protein-calorie malnutrition associated with alcoholic hepatitis. Veterans Administration Cooperative Study Group on Alcoholic Hepatitis

Three hundred sixty-three alcoholic patients with alcoholic hepatitis were studied in six Veterans Administration medical centers. By history, alcohol consumption was 227.9 g per day, with a mean duration of 23.8 years. Cirrhosis accompanied the alcoholic hepatitis in 58.7 percent of the patients who underwent biopsy or autopsy. Complete nutritional assessment was performed in 284 patients, and observed nutritional changes were classified into those associated with marasmus or those characterizing kwashiorkor. A smaller comparison group of 21 alcoholic patients matched for age and alcohol consumption but without clinically evident liver disease was also studied in an identical manner. None of the patients with liver disease was completely free from malnutrition, whereas 62 percent of the alcoholic patients without liver disease showed abnormalities. In patients with alcoholic hepatitis, some findings associated with marasmus were seen in 86 percent, and some features of kwashiorkor were observed in 100 percent. When present together, the complete picture of kwashiorkor and marasmus correlated closely with the clinical severity of the liver disease (p less than 0.005). The nearly constant association of either complete or partial kwashiorkor or marasmus suggests that the separation of these two entities is artificial in alcoholic patients with liver disease. Although, experimentally, malnutrition may not be essential for the development of alcoholic hepatitis, clinically, it appears to precede the development of the liver injury, which suggests an interaction. Recognition is important so that appropriate nutritional therapy can be provided.

Increased intensification and total dose of cyclophosphamide in a doxorubicin-cyclophosphamide regimen for the treatment of primary breast cancer: findings from National Surgical Adjuvant Breast and Bowel Project B-22

PURPOSE

The National Surgical Adjuvant Breast and Bowel Project (NSABP) initiated a randomized trial (B-22) to determine if intensifying but maintaining the total dose of cyclophosphamide (Cytoxan, Bristol-Myers Squibb Oncology, Princeton, NJ) in a doxorubicin (Adriamycin, Pharmacia, Kalamazoo, MI)-cyclophosphamide combination (AC), or if intensifying and increasing the total dose of cyclophosphamide improves the outcome of women with primary breast cancer and positive axillary nodes.

PATIENTS AND METHODS

Patients (N = 2,305) were randomized to receive either four courses of standard AC therapy (group 1); intensified therapy, in which the same total dose of cyclophosphamide was administered in two courses (group 2); or intensified and increased therapy, in which the total dose of cyclophosphamide was doubled (group 3). The dose and intensity of doxorubicin were similar in all groups. Disease-free survival (DFS) and overall survival were determined using life-table estimates.

RESULTS

There was no significant difference in DFS (P = .30) or overall survival (P = .95) among the groups through 5 years. At 5 years, the DFS of women in group 1 was similar to that of women in group 2 (62% v 60%, respectively; P = .43) and to that of women in group 3 (62% v 64%, respectively; P = .59). The 5-year survival of women in group 1 was similar to that of women in group 2 (78% v 77%, respectively; P = .86) and to that of women in group 3 (78% v 77%, respectively; P = .82). Grade 4 toxicity increased in groups 2 and 3. Failure to note a difference in outcome among the groups was unrelated to either differences in amount and intensity of cyclophosphamide or to dose delays and intervals between courses of therapy.

CONCLUSION

Intensifying or intensifying and increasing the total dose of cyclophosphamide failed to significantly improve either DFS or overall survival in any group. It was concluded that, outside of a clinical trial, dose-intensification of cyclophosphamide in an AC combination represents inappropriate therapy for women with primary breast cancer.

Central role of peroxisome proliferator-activated receptors in the actions of peroxisome proliferators

Peroxisome proliferators (PPs) are a large class of structurally dissimilar chemicals that have diverse effects in rodents and humans. Most, if not all, of the diverse effects of PPs are mediated by three members of the nuclear receptor superfamily called peroxisome proliferator-activated receptors (PPARs). In this review, we define the molecular mechanisms of PPs, including PPAR binding specificity, alteration of gene expression through binding to DNA response elements, and cross talk with other signaling pathways. We discuss the roles of PPARs in growth promotion in rodent hepatocarcinogenesis and potential therapeutic effects, including suppression of cancer growth and inflammation.