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Biomedical subjects

B H Cohen

Publications and source records attributed to B H Cohen.

At least 37 records · Page 2Linked to original sources
PubMed1995

Headaches as a symptom of neurological disease.

When a headache develops in a child or adolescent, both the patient and the parents may fear the presence of a brain tumor. However, most headaches are not a symptom of a serious neurological disease but are related to stress or migraine. In this article, headaches in relationship to neurological disorders are reviewed. The pathophysiology of head pain and increased intracranial pressure are reviewed. Methods used to evaluate patients suspected of harboring an intracranial abnormality include a thorough history, a carefully performed physical examination, and neuroimaging studies. This article reviews cerebrovascular disease, neoplasms, hydrocephalus, and other structural abnormalities that cause headaches.

Adolescent↗
PubMed1995

The Burow's triangle scalp reduction. A new and improved technique for paramedian scalp reduction.

BACKGROUND: The paramedian incision for scalp reduction has many advantages over the median (midline-sagittal) incision. OBJECTIVE: This report describes a method by which the paramedian incision may be modified to provide even more advantages. METHODS: In 20 patients with male pattern alopecia, an anterior and posterior paramedian incision was performed along contralateral borders of the bald scalp. The two incisions were joined in the central scalp by a trans-coronal incision. The tissue movement that followed was similar to that of a Burow's triangle advancement flap. RESULTS: The new configuration provided maximal visual access with improved tissue mobilization and ease of handling. Because the tension-bearing vector was directed parallel to the transcoronal incision, there was little tendency for the scar to widen. Because posterior "slots" or "troughs" were not created, additional corrective procedures were not necessary. CONCLUSION: The Burow's triangle scalp reduction design is cosmetically and mechanically more advantageous than traditional median and unilateral paramedian designs of equivalent length.

Alopecia↗
PubMed1995

Prognostic factors and treatment results for supratentorial primitive neuroectodermal tumors in children using radiation and chemotherapy: a Childrens Cancer Group randomized trial.

PURPOSE: To determine clinical characteristics and response to treatment for children with supratentorial primitive neuroectodermal tumors (S-PNETs). PATIENTS AND METHODS: After surgery and staging, 55 patients aged 1.5 to 19.3 years with S-PNETs were randomized to receive craniospinal radiotherapy (RT) followed by eight cycles of 1-(2-chloro-ethyl)-3-cyclohexylnitrosourea (CCNU), vincristine (VCR), and prednisone (standard treatment) or two cycles of 8-in-1 chemotherapy followed by RT and then eight additional cycles of 8-in-1. RESULTS: Three-year Kaplan-Meier estimates (estimate +/- SE) of survival and progression-free survival (PFS) rates for patients with confirmed diagnoses of S-PNET were 57% +/- 8% and 45% +/- 8%, respectively; survival and PFS rates for children with PNETs located in the pineal region were 73% +/- 12% and 61% +/- 13%, respectively, and were significantly different from the other S-PNETs (P < .03). The 8-in-1 arm had greater toxicity than the standard-treatment arm. Distributions of PFS between the two treatment groups were not significantly different (P > .5). Other univariate prognostic factors that influenced PFS included metastasis (M) stage (P < .03: M0 50% +/- 9% v M1-4 0%) and age (P < .02: 1.5 to 2 years 25% +/- 13% v > or = 3 years 53% +/- 9%). CONCLUSION: In this first randomized treatment trial for S-PNETs in children, no significant differences were detected between the two treatment groups. M0 and pineal site of involvement were independent predictors of a better outcome. However, survival was better than previously reported.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1994

Decrease in skin-closing tension intraoperatively with suture tension adjustment reel, balloon expansion, and undermining.

BACKGROUND: The biomechanical and viscoelastic properties of the skin enable it to be significantly stretched within a relatively short period of time. This property, called mechanical creep, is exploited in various surgical maneuvers for intraoperative closure of large surgical defects. The recently introduced Miami Suture Tension Adjustment Reel (S.T.A.R.) device permits both the precise sutured attachment of a linear cycled load to approximate the edges of widened surgical defects, and the easy measurement of wound edge tension across the defects. OBJECTIVE: It was our purpose to compare the relative effects of linear load cycling with the S.T.A.R. device, spherical load cycling with balloon expander, and surgical undermining on the closing tension of surgical defects. METHOD: Surgical wounds were created on the flanks of six pigs and these defects were closed by various methods of repair. The combination of undermining and the S.T.A.R. device ws also evaluated. RESULTS: The average total decreases in skin closing tension were: undermining, 17.8 +/- 0.5%; balloon, 28.5 +/- 1.6%; S.T.A.R. device, 36.6 +/- 4.8%. CONCLUSION: Our data showed that all three techniques were effective in lowering the tension required to approximate surgically created defects, with the S.T.A.R. device proving to be most effective. Undermining and the S.T.A.R. device also worked synergistically to decrease skin-closing tension.

Animals↗
PubMed1994

Medical and surgical management of acute disseminated encephalomyelitis.

Two children with a recent history of viral illness developed visual loss secondary to optic neuritis. Clinical findings and neuroimaging were consistent with acute disseminated encephalomyelitis (ADEM). Markedly elevated opening pressures were noted on lumbar puncture. The patients demonstrated an initial favorable response to high-dose corticosteroid administration. Both had recurrence of symptoms after being tapered off oral corticosteroids. High-dose corticosteroids were reinstituted and a bilateral optic nerve sheath decompression was performed on one patient who developed profound visual loss. A second patient underwent a lumboperitoneal shunt. Both children had resolution of their symptoms and had a recovery of normal visual acuity.

Brain↗
PubMed1993

Scope and strategies of genetic epidemiology: analysis of articles published in Genetic Epidemiology, 1984-1991.

Genetic epidemiology is a relatively new discipline that seeks to unravel the role of genetic factors and their interactions with environmental factors in the etiology of diseases, using population and family study approaches. To characterize the overall direction and emphasis of research strategies used in this field, we reviewed original research articles published in the journal Genetic Epidemiology since its inception in 1984 until the end of 1991. Of 259 published original articles, 92 (35%) focused primarily on methodologic/statistical developments, most commonly in the area of linkage analysis/gene mapping, and 167 (65%) articles were applied or data-derived. Only 42 articles (16%) were population studies, and 217 (84%) were family studies. Most family studies dealt with genetic analysis of pedigree data using segregation and linkage analyses. Of the 137 applied family studies, 73 (53%) were drawn from well-defined populations, and only 40 (29%) considered specific environmental factors in their analyses. These findings clearly indicate a rapid growth in the methodologic and statistical aspects of genetic epidemiology, and in the emphasis on family-based studies and genetic analysis methods. Further developments in genetic epidemiology will require greater integration of epidemiologic approaches of study design and analyses into population and family studies of disease etiology.

Epidemiology↗
PubMed1993

Metabolic and degenerative diseases associated with epilepsy.

Identifying the specific etiology of epilepsy is often difficult. The search for the cause often leads the clinician to suspect inborn errors of intermediary metabolism and other degenerative metabolic diseases. Although these uncommon diseases are often difficult to determine, a correct diagnosis is critical for treatment and genetic counseling. A review of the relevant biochemistry will aid in understanding the pathophysiology of seizures in these conditions. The stream-lined approach to the initial laboratory evaluation that is offered will enable the clinician to screen for most metabolic and degenerative diseases that are associated with epilepsy.

Adolescent↗
PubMed1992

Progressive vision loss. A rare manifestation of familial cavernous angiomas.

We studied four generations of a family in which the index case had progressive loss of vision secondary to a cavernous angioma of the optic nerve and chiasm. Magnetic resonance imaging of the brain revealed multiple, asymptomatic intracerebral cavernous angiomas. Brain magnetic resonance imaging scans of the family members revealed multiple cavernous angiomas in the brother and paternal grandfather, but none in the father or his siblings. Autopsy reports of the paternal great grandfather noted multiple cavernous angiomas in the brain and abdominal viscera. We believe our patient to be the sixth reported case in which a cavernous angioma involved the optic chiasm and optic nerve. Magnetic resonance imaging is a sensitive and specific method of detecting cavernous angiomas. Cavernous angiomas have an autosomal dominant pattern of inheritance with variable penetrance. Surgical intervention in patients with symptomatic cavernous angiomas depends on the location and size of the lesion and associated surgical risks.

Adolescent↗
PubMed1992

Muscle tension patterns during auditory attention.

Although there is much evidence demonstrating muscle tension changes during mental work, there are few data concerning muscle tension patterns during effortful attention to simple sensory stimuli. In the present study, sensory attention was evoked by a pitch discrimination task at three levels of difficulty, with a digit retention task administered for comparison. Twenty-four females each performed both tasks at all levels of difficulty, while the EKG, and the corrugator supercilii, frontalis, lip, jaw, chin, and forearm area EMG were recorded. As expected, heart rate decreased significantly with increasing difficulty of the pitch task. A pattern of facial EMG responses accompanied the pitch task, which included significant increases in corrugator and frontalis, and decreases in the jaw as a function of difficulty, and time within trials. The tension pattern observed during sensory intake is discussed in terms of its relation to emotional expressions and motor theories of attention.

Acoustic Stimulation↗
PubMed1992

Estimating familial aggregation while adjusting for covariates. Application to pulmonary function data from black and white sibships.

Although crude correlations are useful in family studies, some adjustment for effects of risk factors that vary both within and among families if often needed. A linear model for estimating sibship correlations while simultaneously considering height, age, race, sex, ascertainment, and smoking status was used on pulmonary function data on 1-second forced expiratory volume (FEV1) and the natural logarithm of the ratio of FEV1 to forced vital capacity (lnFEV%) from 402 adults in 152 white sibships and 172 adults in 59 black sibships. Crude correlations of .271 +/- .048 (FEV1) and .342 +/- .047 (lnFEV%) decreased significantly to .206 +/- .048 and .231 +/- .048, respectively, after adjustment. For black and white sibs, adjusted intraclass correlations, although not statistically different, were .153 +/- .089 and .225 +/- .055 (FEV1), respectively, and were .103 +/- .088 and .275 +/- .054 (lnFEV%), respectively, suggesting that pulmonary function may aggregate more strongly among whites. This analysis illustrates how risk factor adjustment can be readily incorporated into familial correlation studies.

Adult↗
PubMed1992

The suture tension adjustment reel. A new device for the management of skin closure.

The initial clinical experience with a new device, called the Suture Tension Adjustment Reel (STAR), is described. The historical precedence and rationale underlying linear tissue expansion is presented. Case reports illustrate the use of the STAR for preoperative tissue stretching, for intraoperative tissue stretching, and for tissue mobilization as applied to scalp reduction surgery. The multipurpose device is a safe, simple, and reliable adjunct to sutured surgery. It is of value in the general management of tensioned and nontensioned skin closures.

Adult↗
PubMed1991

Applications of the concept of attributable fraction in medical genetics.

Attributable fraction, the fraction of cases of a disease in a population attributed to a particular risk factor, is a useful measure in the design and interpretation of epidemiologic studies of disease etiology. We review here the applications of the concept of attributable fraction in medical genetics. Specifically, attributable fraction can be used 1) in studies of the association between genetic traits and specific diseases to quantitate the contribution of specific alleles to disease occurrence in a population; 2) in population studies of mutations and birth defects to estimate the impact of mutagens and teratogens; and 3) in genetic analyses of family data, to evaluate the contribution of putative single gene loci to disease etiology. In the latter context, the concept of attributable fraction can be contrasted with the more commonly used concept of heritability. Examples from the literature provide illustrations of the usefulness of attributable fraction in medical genetic studies.

Alleles↗
PubMed1991

Improved survival with the use of adjuvant chemotherapy in the treatment of medulloblastoma.

Between 1975 and 1989, 108 children with newly diagnosed medulloblastoma/primitive neuroectodermal tumor (MB/PNET) of the posterior fossa were treated at the authors' institution. The patients were managed uniformly, and treatment included aggressive surgical resections, postoperative staging evaluations for extent of disease, and craniospinal radiation therapy with a local boost. Beginning in 1983, children with MB/PNET were prospectively assigned to risk groups; those with "standard-risk" MB/PNET were treated with radiation therapy alone, while those in the "poor-risk" group received similar radiation therapy plus adjuvant chemotherapy with 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU), vincristine, and cisplatin. The 5-year actuarial disease-free survival rate for all patients treated between 1975 and 1982 was 68%, and 73% when patients who died within 2 weeks after operation were excluded. This survival rate was statistically better for patients treated after 1982 (82%) compared to those treated between 1975 and 1982 (49%) (p less than 0.004). There was no difference in disease-free survival rates over time for children with standard-risk factors; however, there was a significant difference in the 5-year survival rate for poor-risk patients treated prior to 1982 (35%) compared to those treated later (87%) (p less than 0.001). For the group as a whole, a younger age at diagnosis correlated with a poorer survival rate; however, this relationship between age and outcome was significant only for children treated before 1983 (p less than 0.001). These results demonstrated an encouraging survival rate for children with MB/PNET, especially those treated with aggressive surgical resection followed by both radiation therapy and chemotherapy. The results strongly suggest that chemotherapy has a role for some, and possibly all, children with MB/PNET.

Adolescent↗
PubMed1990

Hyperfractionated radiotherapy for children with brainstem gliomas: a pilot study using 7,200 cGy.

Brainstem gliomas, constituting approximately 10% of all childhood central nervous system tumors, remain the most resistant of all brain tumors to therapy. A subgroup of high-risk patients with tumors that diffusely involve the brainstem or that microscopically demonstrate foci of anaplasia on biopsy specimens rarely survive after treatment. Conventional doses of radiotherapy result in temporary clinical improvement in the majority of these high-risk patients; however, few if any remain alive 18 months after treatment. Hyperfractionated radiotherapy, with delivery of larger numbers of smaller fractions of radiotherapy, is a possible way to increase tumor control without increasing neurological toxicity. In 1985, a multiinstitutional phase I/phase II trial, using 100 cGy of radiation therapy twice daily to a total dose of 7,200 cGy, was undertaken for patients with high-risk brainstem gliomas. At the time of writing, 24 (69%) had developed progressive disease and 11 remained in continuous progression-free remission. Actuarial progression-free survival at 20 months is approximately 30%. Twenty-three of 31 evaluable patients had an objective radiographic response to therapy. In comparison to both historical control patients and patients treated in a previous trial using 6,480 cGy of hyperfractionated radiation therapy, there was a statistically significant improvement in progression-free survival rate for patients treated with 7,200 cGy of hyperfractionated radiation therapy (p less than 0.01). To date no patient has died as a result of treatment. Six patients developed transient neurological deterioration or cystic intralesional changes, as demonstrated on magnetic resonance imaging, within 6 weeks of the completion of radiotherapy. Postmortem examination performed in 7 patients did not disclose significant radiation necrosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Major genetic mechanisms in pulmonary function.

Regressive models were used to search for possible major gene effects on pulmonary function in two groups of families: one ascertained through patients with chronic obstructive pulmonary disease [COPD defined as forced expiratory volume in one second (FEV1) less than 70% forced vital capacity (FVC)] and the other ascertained through patients with non-pulmonary disorders. There were 85 COPD families with data on 270 individuals and 56 non-pulmonary families with data on 199 individuals. The analysis was done on residuals obtained from a regression of FEV1 on age, sex, race, height, and ascertainment group. Smoking status was incorporated directly as a covariate in the regressive models. Data on probands were excluded in this analysis as a partial correction for ascertainment bias. The best fitting model for the 85 COPD families included a major gene effect with sex specific variances, but no residual familial correlation. The best fitting model for the non-pulmonary families was one with no major gene effect and no residual familial correlation. Cigarette smoking was a significant covariate in both groups of families. Testing for heterogeneity showed a significant difference in the control of pulmonary function among these COPD and non-pulmonary families (X2 = 20.12 on 6 df; p = 0.0026). Major gene effects appear to be limited to these COPD families, while there was no evidence for major gene effects in the non-pulmonary families.

Adult↗