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Biomedical subjects

J C Dean

Publications and source records attributed to J C Dean.

At least 73 records · Page 4Linked to original sources
PubMed1991

A new method for assessing relative dynamic motion of vertebral bodies during cyclic loading in vitro.

A new experimental technique for measuring generalized three-dimensional motion of vertebral bodies during cyclic loading in vitro is presented. The system consists of an orthogonal array of three lasers mounted rigidly to one vertebra, and a set of three mutually orthogonal charge-coupled devices mounted rigidly to an adjacent vertebra. Each laser strikes a corresponding charge-coupled device screen. The mathematical model of the system is reduced to a linear set of equations with consequent matrix algebra allowing fast real-time data reduction during cyclic movements of the spine. The range and accuracy of the system is well suited for studying thoracolumbar motion segments. Distinct advantages of the system include miniaturization of the components, the elimination of the need for mechanical linkages between the bodies, and a high degree of accuracy which is not dependent on viewing volume as found in photogrammetric systems. More generally, the spectrum of potential applications of systems of this type to the real-time measurement of the relative motion of two bodies is extremely broad.

Equipment Design↗
PubMed1991

Apparent Fryns' syndrome and aneuploidy: evidence for a disturbance of the midline developmental field.

A premature male infant is described in whom the presence of coarse facies, diaphragmatic hernia, genital anomalies and Dandy-Walker malformation suggested a diagnosis of Fryns' syndrome. Lymphocyte karyotype revealed a partial trisomy 22, and his mother carried an apparently balanced 11/22 translocation. Three infants have been described recently with features of Fryns' syndrome and various aneuploidies. It is suggested that amplified developmental instability of the midline developmental field may account for some of the phenotypic resemblances between these cases.

Abnormalities, Multiple↗
PubMed1991

Interstitial deletion of chromosome 13: prognosis and adult phenotype.

A de novo interstitial deletion of chromosome 13 (46,XY,del(13)(pter----q14.3::q22.3----qter] is described in a 22 year old man with severe mental retardation, poor language development, low set ears, hypertelorism, broad nasal bridge, short hands and fingers, and a history of swallowing disorder in childhood with subsequent dyspepsia. The dysmorphic features did not become evident until later childhood, supporting the view that karyotyping should be performed routinely in all children with developmental delay.

Abnormalities, Multiple↗
PubMed1991

Type III collagen mutations cause fragile cerebral arteries.

Premature vascular aneurysms and fragility of cerebral arteries are commonly associated with type III collagen mutations and physical signs suggesting a generalized abnormality of connective tissue. Sometimes these traits are clearly genetically transmitted. Here we present seven examples of early cerebrovascular aneurysms or fragility including five examples of carotid cavernous sinus aneurysms. With one exception in which we suspect the mutation is too small to be detected, all of them had easily visible abnormalities of their type III collagen proteins. Further work in progress will eventually allow the characterization of their mutations at gene sequence level and will be followed by the ability to prevent transmission of the mutant genes in these families.

Adult↗
PubMed1990

Isolated hypogonadotrophic hypogonadism: a family with autosomal dominant inheritance.

A family is reported in which isolated hypogonadotrophic hypogonadism is inherited as an autosomal dominant condition with variable expression. In previous familial cases, inheritance was autosomal recessive. Comparison is made with the endocrine and genetic findings in Kallmann's syndrome, which should be considered a separate disorder. There is difficulty in drawing a sharp distinction between hypogonadotrophic hypogonadism and constitutional delay in puberty in this family.

Adolescent↗
PubMed1990

Prevention of intractable partial seizures by intermittent vagal stimulation in humans: preliminary results.

Intermittent stimulation of the vagus nerve in four patients resulted in complete seizure control in two, a 40% reduction of seizure frequency in one, and no change in seizure frequency in the other. Side effects (hoarseness, stimulation sensation in the neck, and hiccups) were transient and occurred concomitantly with stimulation. All patients tolerated increasing stimulation parameters well. The results, however, are inconclusive because of the brief duration (6-12 months) of follow-up. Vagal stimulation represents a novel approach for seizure control in patients who have intractable epilepsy, but additional studies are needed to clarify the efficacy and safety of the procedure and to define selection criteria for patients.

Adult↗
PubMed1990

Cranial hemihypertrophy and neurodevelopmental prognosis.

Three cases of congenital cranial hemihypertrophy are described. CT or ultrasound scans showed unilateral cerebral enlargement with dilatation of the ipsilateral ventricle. Seizures occurred in two patients and the neurodevelopmental outlook appears poor. These patients represent a poor prognosis subgroup of the congenital hemihypertrophies.

Brain↗
PubMed1989

Juvenile myoclonic epilepsy: long-term response to therapy.

Data from 50 patients with juvenile myoclonic epilepsy (JME) were analyzed retrospectively to assess the response to drug therapy--long-term seizure control, relapse rates, and confounding factors in seizure recurrence. Valproate is the only available antiepileptic drug that has been shown to be effective in controlling the generalized seizure components of JME--myoclonic, tonic--clonic, and absence seizures--without significant side effects. Data were collected using the EpiMonitor software and represented case follow-up from 2 months to 9 years. Forty-three patients (86%) were seizure free for at least 1 year; 25 patients (50%) relapsed at some point during follow-up. Relapses were precipitated most frequently by fatigue, noncompliance, stress, sleep deprivation, and alcohol consumption. With accurate diagnosis and appropriate therapy, seizures in JME can be adequately controlled, although JME is a chronic disorder that may require lifelong therapy. To minimize relapse, patient management must also focus on patient lifestyle to eliminate or control lifestyle-associated precipitants of seizure relapse.

Adolescent↗
PubMed1989

The scope and use of valproate in epilepsy.

Valproate has rapidly advanced as an antiepileptic drug in the last 15 years. This simple branched-chain fatty acid is strikingly different from previous antiepileptic drugs. Numerous clinical studies have found valproate to be highly effective in controlling generalized seizures, particularly as monotherapy. Ideally, valproate is given in three to four doses per day, because the elimination half-life varies from 6 to 15 hours, depending on concomitantly administered drugs and metabolic variations. Increasing the dosage raises the peak serum level and also increases the duration of time during which a minimum effective serum concentration is obtained. Drug interactions occur when valproate is administered with other drugs, especially other antiepileptic drugs. Side effects attributed to valproate include tremor, weight gain, hair loss, hair growth, hepatotoxicity, and neural tube defects in offspring of mothers. Monitoring serum valproate concentrations and seizure frequency are essential aspects of patient follow-up.

Epilepsy↗
PubMed1989

The Flexi-Flate and Flexi-Flate II penile prostheses.

Our experience with 45 recipients of the Flexi-Flate and Flexi-Flate II prostheses leads us to the following conclusions: 1. The device is readily implantable in approximately 1 hour with techniques familiar to most urologists who have implanted rigid or semirigid rods. 2. With attention to detail, prosthesis sizing is straightforward using intraoperative determination of corporeal girth and total corporeal length. We were unable reliably to predict prosthesis size preoperatively. Hence, as with other inflatable prostheses, we recommend that an entire range of prosthesis sizes be available at implantation. 3. Mechanical reliability is similar to that of more complex inflatable devices. The mechanical malfunction rate has been 11.6 per cent over a 15.1-month follow-up. 4. Patients find the inflation-deflation mechanisms easy to master. 5. Spontaneous deflation does occur during intercourse in some instances, but most patients are able to adjust sexual techniques and position satisfactorily with minimal disruption of enjoyment for themselves and their partners. 6. Among individuals with functional prostheses, a detailed survey of patient and partner response postoperatively revealed a high level of satisfaction for both and a return to premorbid levels of sexual functioning. Concealability was good in the flaccid state, and patients report minimal difficulties or embarassment with everyday functions in public restrooms and shower situations.

Consumer Behavior↗
PubMed1988

Valproate monotherapy in partial seizures.

Results of a retrospective study in 30 patients indicate that, contrary to the findings of some earlier studies, valproate monotherapy is highly effective in the treatment of partial seizures, especially those that become secondarily generalized. In 22 of these 30 patients (73 percent), valproate monotherapy either abolished seizures (12 patients) or reduced their frequency by at least 51 percent (10 patients), whereas eight patients experienced minimal or no reduction in seizure frequency. All these patients had previously experienced treatment failure with carbamazepine, phenytoin, or phenobarbital--either alone or combined--because of lack of efficacy or unacceptable side effects. In these patients, failure to have a response to valproate therapy appeared to be related to the type of seizure (simple partial seizures alone/complex partial seizures alone, without secondarily generalized tonic-clonic seizures) and longer duration of uncontrolled seizures. Although these results cannot be generalized to all patients with partial seizures, they do indicate that a double-blind randomized trial of valproate in patients with all types of partial seizures is warranted.

Adolescent↗
PubMed1988

Clinical experience with a self-contained inflatable penile implant: the Flexi-Flate.

We implanted 23 Flexi-Flate penile prostheses during a 15-month period beginning July 1985. Of the implants 22 were followed for a mean of 16.1 months and 19 (86 per cent) function well. Satisfaction of individuals with a functioning prosthesis, as determined by interview and questionnaire (79 per cent response rate), has been good. Deflation sometimes occurs with penile shaft bending during sexual activity but this is managed satisfactorily by most couples via technique adjustments with minimal disruption of enjoyment. Reliable preoperative prosthesis size selection based on pubis to mid glans measurements was not possible in our hands secondary to broad variation in intracorporeal lengths found in the population studied.

Adult↗
PubMed1987

Collegiate alcohol/drug treatment programs in the United States.

A random sample of 400 U.S. colleges and universities provided data on the existence, type, structure, and philosophy of campus alcohol/drug treatment programs. Although many institutions reported service provision, a variety of approaches were described in the questionnaires. The results uncover important issues on administrative structure, licensure, treatment models, assessment procedures, and confidentiality.

Adolescent↗
PubMed1986

Alcohol and drug collegiate treatment programs: a proposal.

The study describes key elements of an administrative and clinical structure for campus alcohol/drug treatment programs. The description is the product of a national study of collegiate alcohol/drug treatment programs in the United States, and the administrative and clinical experience of the authors. It is suggested that the administrative structure be an integral part of the campus organization. The need for sophisticated clinical assessment and treatment techniques is emphasized.

Adult↗
PubMed1985

Diagnostic ultrasound in pediatric oncology.

Sonography is an extremely versatile diagnostic tool for the assessment of cancer in children, offering several advantages over other imaging modalities, chief of which is its truly noninvasive nature. In view of the available comparative studies and the risk/benefit and cost/benefit ratios of the imaging procedures available, ultrasound is attractive for use as the initial study of many pediatric mass lesions. Its availability, ease of application, and lower cost also favor its use in the assessment of the child with known or suspected malignancy.

Abdomen↗
PubMed1985

The human tumor clonogenic assay in human breast cancer.

The human tumor clonogenic assay (HTCA) was evaluated in 407 fresh samples of breast cancer from 288 patients. Seventy samples were inadequate for testing. Adequate in vitro growth for drug testing (greater than 30 colonies/plate) was obtained in 91 (27%) of the 337 viable samples, inadequate growth for drug evaluation (5 to 30 colonies/plate) in 17%, and no colony formation (less than 5 colonies/plate) in 56%. Operationally defining a greater than or equal to 50% inhibition of colony formation as in vitro drug sensitivity, the in vitro response rates to 12 anticancer drugs tested against ten to 36 different cancers (arranged in decreasing order according to the number of tests performed) were as follows: doxorubicin (14%), bisantrene (54%), vinblastine (33%), mitomycin (36%), interferon clone A (23%), 5-fluorouracil (20%), methotrexate (17%), leukocyte interferon (33%), mitoxantrone (42%), cyclophosphamide (25%), m-AMSA (16%), and melphalan (10%). Among 25 patients receiving single-agent therapy, there were ten (59%) of 17 with in vitro sensitivity who responded; resistance was correctly predicted in nine patients (100%), P = .01. Among 34 patients treated with combination chemotherapy, seven (50%) of 14 with in vitro sensitivity responded, and resistance was predicted in 13 (65%) of 20 patients. Difficulties in using the HTCA in breast cancer (including small specimen size, difficulties in disaggregation, and inadequacy of growth) will require additional research. Nonetheless, the assay appears to detect in vitro activity as well as resistance of a variety of anticancer agents and appears to predict clinical responsiveness to standard as well as some investigational single agents.

Antineoplastic Agents↗