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Biomedical subjects

J W Patterson

Publications and source records attributed to J W Patterson.

At least 19 recordsLinked to original sources
PubMed1992

3-Carboxy-5-methyl-N-[4-(trifluoromethyl)phenyl]-4-isoxazolecarboxamide, a new prodrug for the antiarthritic agent 2-cyano-3-hydroxy-N-[4-(trifluoromethyl)phenyl]-2-butenamide.

The title compound 3-carboxyisoxazole 3 was synthesized by cycloaddition of carbethoxyformonitrile oxide to N-[4-(trifluoromethyl)phenyl]-3-pyrrolidino-2-butenamide (6) with spontaneous elimination of pyrrolidine followed by hydrolysis of the ethyl ester. Compound 3 was shown to be absorbed intact after oral administration to rats. Over 24 h, the compound was metabolized to yield plasma concentrations of the antiinflammatory agent 2-cyano-3-hydroxy-N-[4-(trifluoromethyl)phenyl]-2-butenamide (2), similar to those obtained following an equivalent dose of the established prodrug of 5-methyl-N-[4-(trifluoromethyl)phenyl]isoxazole-4-carboxamide (1).

Aniline Compounds↗
PubMed1992

D600 increases the resistance associated with the equatorial potassium current of the lens.

The effects of D600, the methoxy analog of verapamil, on a pCMPS system were studied. A major effect of D600 is to increase the resistance associated with the equatorial potassium current of the lens. The increase in resistance is statistically significant at concentrations above 200 microM. At concentrations of 25-50 microM, D600 counteracts the decrease in resistance produced by binding sulfhydryl groups with 1 microM pCMPS. This effect is similar to that produced by quinine and by a calcium-free medium, and is attributed to the prevention of an increase in the calcium-dependent conductance produced by pCMPS.

4-Chloromercuribenzenesulfonate↗
PubMed1992

Ultrastructural changes in acquired perforating dermatosis.

We performed ultrastructural studies of skin lesions in seven adults with acquired perforating dermatosis. Three of the patients had diabetes mellitus and two were undergoing hemodialysis. Lesions in an early stage showed exocytosis of inflammatory cells and alteration of elastic fibers. Lesions in an intermediate stage featured discontinuities of the basement membrane and aggregates of electron-dense material lateral to the perforated focus, together with dermal edema, scattered macrophages, and densely aggregated collagen fibers that focally filled the papillary dermis. Later-stage lesions showed fibroblasts in the dermis and degenerated elastic fibers within transepidermal channels. In most cases there was a single large epidermal channel lined by flattened epithelial cells, and containing a variety of cellular and extracellular materials. Small "secondary" channels without abnormal keratinization were also observed within the epidermis. The findings suggest that altered keratinization is limited to the immediate vicinity of well-formed transepidermal channels, and that exocytosis of inflammatory cells and alterations of elastica are early and possibly key changes in lesion development. The unexpected discovery of hair fragments in one case suggests that curled hairs may play a role in the pathogenesis of some cases of acquired perforating dermatosis.

Adult↗
PubMed1992

Link between the ciliary process and lens equatorial current.

Circadian and seasonal rhythmic changes in the intraocular pressure are modulated by the nervous system and expressed in the eye by the release of norepinephrine at adrenergic nerve endings. This study links seasonal changes and the effects of the topical application of norepinephrine with changes in the equatorial current of the lens in frogs. A vibrating probe and microelectrodes were used to study the segment of the K+ electrical loop extending between the internal microelectrode, used for measuring potential difference (PD), and the external vibrating electrode, measuring the equatorial current (J). Changes were noted in the electrophysiological parameters of 270 normal frog lenses (Rana pipiens) at different times of the year. Threefold seasonal variations were observed in the amplitude of equatorial current (J) and the resistance associated with the equatorial current (RJ). J was greatest in the winter and RJ was greatest in late spring. Norepinephrine applied directly to the lens did not affect the equatorial current. Norepinephrine applied topically, increased the equatorial current of the lens. It is concluded that the magnitude of the equatorial current of the lens is mediated in part by the ciliary process epithelium.

Administration, Topical↗
PubMed1992

Lymphomas.

The diagnosis of lymphoma currently relies on a combination of clinical, routine histopathologic, and immunohistochemical studies, sometimes supplemented by other special techniques such as flow cytometry, DNA analysis, and gene rearrangement study. This review considers the practical diagnosis of cutaneous lymphoma, with particular emphasis on three areas: Hodgkin's disease, non-Hodgkin's lymphomas and their differentiation from lymphocytoma cutis, and mycosis fungoides and other T-cell lymphomas.

Hodgkin Disease↗
PubMed1991

Cutaneous metastasis from papillary carcinoma of the thyroid gland.

Cutaneous metastases from carcinoma of the thyroid gland are rare. We present the clinical, histologic, and immunohistochemical features of a solitary metastasis from papillary carcinoma of the thyroid. Our results indicate that this tumor can produce epithelial mucin and, therefore, must be differentiated from other metastatic carcinomas and from primary apocrine tumors of the skin. Positive staining for thyroglobulin confirmed the diagnosis in this case.

Carcinoma, Papillary↗
PubMed1991

Lichenoid histopathologic changes in patients with clinical diagnoses of exfoliative dermatitis.

Among 30 patients who received a clinical diagnosis of exfoliative dermatitis and were biopsied between 1982 and 1990, nine showed microscopic features of lichenoid dermatitis. Clinical information was available in eight of these cases. Possible etiologic factors included lymphoma, herpes simplex infection, connective tissue disease, and (in five cases) reactions to drugs. In each instance, microscopic features included a superficial perivascular lymphocytic infiltrate involving the dermal-epidermal interface, vacuolar alteration of the basilar layer, and individually necrotic keratinocytes at all levels of the epidermis. Such microscopic changes are not usually described in connection with exfoliative dermatitis, with the possible exception of those cases related to lichen planus or lupus erythematosus. Disseminated lichenoid drug eruption is one possible interpretation of the drug-induced cases. Erythema multiforme is another condition that has similar microscopic features and has been associated with drugs (many of which also cause exfoliative dermatitis), infectious agents, neoplasms, and connective tissue diseases. Lichenoid dermatitis can become generalized and clinically mimic and exfoliative dermatitis. Many, but not all, of these eruptions may be triggered by drugs.

Adult↗
PubMed1991

Meningoceles, meningomyeloceles, and encephaloceles: a neuro-dermatopathologic study of 132 cases.

Because there have been few comprehensive histopathologic studies of meningomyeloceles and related malformations, we undertook a systematic study of these lesions. One hundred and thirty two cases were obtained from our surgical pathology files; these included 38 meningoceles, 71 meningomyeloceles, and 23 encephaloceles. Tissue sections were stained with hematoxylin and eosin; special stains included trichrome, alcian blue, Fontana-Masson, Nissl, Holzer, and immunoperoxidase for glial fibrillary acidic protein. Epithelial changes included ulceration, atrophy, or nevoid hyperplasia of the epidermis, and loss of appendages. Mesodermal features included fibrous zones resembling dura, subarachnoid tissue or scar (99% of cases), increased numbers of blood vessels (83%), hypertrophy of arrector pili muscle (42%), lipoma formation (38%), and immature skeletal muscle fibers (5%) that rarely intermingled with neuropil-like matrix. The latter tissue was identified in 71% of cases and included neurons, astrocytes, oligodendroglia, and ependyma. Forty-eight percent of cases included peripheral nerve fibers or roots, and some fibers formed onion bulb or Pacinian corpuscle-like structures. Meningothelial cells were observed in 26% of cases and sometimes formed recognizable whorls. Choroid plexus was noted in 3 cases, one example showing an unusual dystrophic calcification that formed long parallel spicules. Pigmented dendritic cells were observed within zones of fibrous tissue in 10% of cases. These malformations involve complex arrangements of cutaneous, neuroectodermal, and mesodermal elements. Because they may be encountered by dermatopathologists, familiarity with the microscopic features of dysraphic lesions is essential.

Encephalocele↗
PubMed1991

Effects of oxidants on lens transport.

Hydrogen peroxide is associated with the development of cataracts. As an oxidant, it can act on the sulfhydryl groups of proteins and alter the transport properties of membranes. A nearly impermeant sulfhydryl binding agent is p-chloromercuriphenylsulfonate (p-CMPS). The changes in the current-voltage relationship of the equatorial potassium current produced by hydrogen peroxide and p-CMPS are similar. The authors studied the effects of p-CMPS to determine the possible effects of binding extracellular sulfhydryl groups. With a vibrating probe and microelectrodes, the authors saw three sequential effects of 0.5-5.0 microM p-CMPS. The first phase was a shift of the reversal potential, which is equivalent to the potassium equilibrium potential, to more negative values. The current-voltage relationship (J vs PD) shifted in a manner opposite to that produced by ouabain. The 86Rb uptake was stimulated. Ouabain blocked this initial phase. The second phase was a decrease in the resistance. The effects seen were similar to those described in other tissues after the intracellular injection of small amounts of Ca++. This second phase was inhibited by the removal of Ca++ from the medium and also by the addition of quinine to the medium. The third phase consisted of a depolarization of the lens. This effect has been described by others with larger concentrations of p-CMPS and is accompanied by an influx of Na+ and Ca++. The results suggested that micromolar quantities of extracellular p-CMPS sequentially stimulate the Na, K-pump; activate Ca(++)-dependent K+ channels; and open nonspecific channels. It is suggested that the second phase may play a role in cateractogenesis.

4-Chloromercuribenzenesulfonate↗
PubMed1990

Congenital midline hamartoma: case report with histochemical and immunohistochemical findings.

We report the case of a polypoid nodule on the chin of an infant. Microscopically, the lesion featured numerous pilosebaceous units, eccrine sweat glands, arrectores pilorum muscles, mature adipose tissue, and prominent admixtures of skeletal muscle. This lesion has much in common with the accessory tragus, and is similar to the one reported earlier as rhabdomyomatous mesenchymal hamartoma. We feel the more general term congenital midline hamartoma is preferable, as it encompasses both the clinical and microscopic features of the lesion.

Chin↗
PubMed1979

Localized tick bite reaction.

A woman presented with a localized tick bite reaction. The tick (Amblyomma americanum, the "lone star" tick) was still attached to the erythematous, indurated skin of the upper back. After several unsuccessful attempts at removal, a punch biopsy was performed, and the resultant histologic sections incorporated both tick and involved skin. The various systemic and localized tick bite reactions are discussed, as are the diagnostic dilemmas which may arise when the organism is no longer present. Punch biopsy is suggested as an effective means of removing the organism.

Aged↗