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Biomedical subjects

R C Read

Publications and source records attributed to R C Read.

At least 19 recordsLinked to original sources
PubMed1992

Interaction of capsulate Haemophilus influenzae with human airway mucosa in vitro.

Two pairs of isogenic capsulate and noncapsulate and one pair of capsulate fimbriate and nonfimbriate strains of Haemophilus influenzae type b were studied in an organ culture of human respiratory mucosa. Over 24 h, the numbers of recovered bacteria increased from the original inoculum size of 10(5) to 10(8) CFU/ml. Transmission electron microscopy and scanning electron microscopy showed that noncapsulate organisms caused significant epithelial damage, whereas capsulate strains did not. Association of noncapsulate bacteria with damaged epithelial cells was observed by 14 h of incubation. In contrast, capsulate organisms were associated with a dense, thick, gel-like matrix which was observed above the epithelial surface. These capsulate organisms were not seen to associate with the epithelial surface (by transmission electron microscopy), though they were occasionally seen adhering to cells by scanning electron microscopy. Fimbriate capsulate H. influenzae showed increased adherence to buccal cells compared with nonfimbriate capsulate organisms. There was also association of fimbriate capsulate bacteria with damaged organ culture epithelium in one of four experiments. It is concluded that both capsule and fimbriae affect the interaction of H. influenzae with human airway mucosa in vitro by influencing adherence to and damage of the epithelium.

Bacterial Adhesion↗
PubMed1992

Effect of Pseudomonas aeruginosa rhamnolipids on mucociliary transport and ciliary beating.

Pseudomonas aeruginosa rhamnolipid causes ciliostasis and cell membrane damage to rabbit tissue, is a secretagogue in cats, and inhibits epithelial ion transport in sheep tissue. It could therefore perturb mucociliary clearance. We have investigated the effect of rhamnolipid on mucociliary transport in the anesthetized guinea pig and guinea pig and human respiratory epithelium in vitro. Application of rhamnolipid to the guinea pig tracheal mucosa reduced tracheal mucus velocity (TMV) in vivo in a dose-dependent manner: a 10-microgram bolus caused cessation of TMV without recovery; a 5-micrograms bolus reduced TMV over a period of 2 h by 22.6% (P = 0.037); a 2.5-microgram bolus caused no overall changes in TMV. The ultrastructure of guinea pig tracheal epithelium exposed to 10 micrograms of rhamnolipid in vivo was normal. Application of 1,000 micrograms/ml rhamnolipid had no effect on the ciliary beat frequency (CBF) of guinea pig tracheal rings in vitro after 30 min, but 250 micrograms/ml stopped ciliary beating after 3 h. Treatment with 100 micrograms/ml rhamnolipid caused immediate slowing of the CBF (P less than 0.01) of human nasal brushings (n = 7), which was maintained for 4 h. Mono- and dirhamnolipid had equivalent effects. The CBF of human nasal turbinate organ culture was also slowed by 100 micrograms/ml rhamnolipid, but only after 4 h (CBF test, 9.87 +/- 0.41 Hz; control, 11.48 +/- 0.27 Hz; P less than 0.05, n = 6), and there was subsequent recovery by 14 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Cooper's posterior lamina of transversalis fascia.

The original description of the transversalis fascia and the internal inguinal ring by Astley Cooper in 1804 is recounted along with the immediate recognition of its importance by other surgical anatomists. The description he made in 1807 of two laminae has been essentially ignored or denied. The deep posterior lamina has been confused with a membranous condensation in the preperitoneal fascia. However, Lytle and Fowler reported a secondary or deeper internal ring and Mackay described the inferior epigastric artery perforating the transversalis fascia at its origin and then coursing cephalad on it to enter the rectus sheath anterior to the arcuate line. My experience with preperitoneal exposure of groin herniae, from the anterior and posterior approach, has demonstrated a posterior lamina deep to the epigastric vasculature attached to the pubic ramus. Repair of inguinal herniae should begin in the preperitoneal layer internal to Astley Cooper's bilaminar transversalis fascia and the epigastric vessels. This will ensure ligation of any peritoneal sac within the iliac fossae, as recommended by Bassini, or internal to the false neck, as described by Henry. This is the avascular, fissile, envelope in which Stoppa has so successfully placed prostheses.

Anatomy↗
PubMed1991

Interaction of nontypable Haemophilus influenzae with human respiratory mucosa in vitro.

One laboratory strain (SH9) (n = 12) and five clinical isolates of unencapsulated Haemophilus influenzae replicated from 10(4) to 10(8) cfu/ml over 24 h in an organ culture of human respiratory mucosa in which only the intact mucosal surface is exposed. By transmission electron microscopy (TEM), bacteria were not seen in association with normal respiratory epithelium, even after incubation for 24 h. Histology and TEM morphometry demonstrated patchy and occasionally confluent damage to epithelia at this time, with bacteria associated only with cells that were structurally damaged. Scanning electron microscopy revealed an increased quantity of mucus in infected preparations; H. influenzae were associated with mucus by 14 h of incubation and with damaged epithelial cells by 24 h. Fimbriation of H. influenzae increased buccal cell adherence but did not facilitate association with normal respiratory epithelium and failed to increase epithelial damage or association with damaged cells. Epithelial damage may be prerequisite for association of H. influenzae with respiratory epithelium in vitro.

Bacterial Adhesion↗
PubMed1991

Ciliary beat frequency and structure of recipient and donor epithelia following lung transplantation.

To investigate possible changes following lung transplantation, the structure and in vitro ciliary beat frequency (CBF) of airway epithelium from the cytology brushings of 9 heart-lung (HLT) and 5 single-lung (SLT) transplant recipients were examined. The CBF of brushings taken proximal and distal to the anastomosis was measured 2-10 months following transplant. There was no difference between the measured mean CBF at the two sites or between the two groups; HLT CBF: distal 11.0 +/- 0.5 Hz (standard error of mean), proximal 10.5 +/- 0.4 Hz, SLT CBF: distal 11.7 +/- 0.9 Hz, proximal 12.0 +/- 0.6 Hz. Mean CBF of bronchial brushings (except distal brushings from SLT patients) was significantly lower than that from controls: 13.6 +/- 0.3 Hz (n = 7) (p less than 0.05). Transmission electron microscopy of epithelial brushings from 4 patients (3 HLT, 1 SLT) revealed epithelial abnormalities both proximal and distal to the anastomosis, particularly ciliary depletion, mitochondrial abnormalities and death of cells. No significant ciliary ultrastructural abnormalities were seen in any tissue. We conclude that epithelial abnormalities were observed both proximal and distal to the anastomosis following lung transplantation. These may contribute to impairment of mucociliary clearance.

Bronchi↗
PubMed1990

Intrapleural tetracycline for the prevention of recurrent spontaneous pneumothorax. Results of a Department of Veterans Affairs cooperative study.

This prospective, multicenter, randomized, "unblinded," controlled clinical trial was designed to determine if the intrapleural instillation of 1500 mg of tetracycline hydrochloride would be effective in diminishing the ipsilateral rate of recurrence for spontaneous pneumothorax. During the 4-year enrollment period, 113 patients were assigned to the tetracycline group; 116 patients were assigned to the control group. During the 5-year study period, the recurrence rate in the tetracycline group (25%) was significantly less than that in the control group (41%). Use of tetracycline seemed to reduce the recurrence rates for patients with either primary or secondary spontaneous pneumothorax and for patients with either an initial or a recurrent pneumothorax. We conclude that the intrapleural administration of tetracycline in patients with spontaneous pneumothorax significantly reduces the rate of ipsilateral recurrence but is associated with intense chest pain. Intrapleural tetracycline therapy is indicated for patients with a spontaneous pneumothorax who are hospitalized and are treated with tube thoracostomy.

Adult↗
PubMed1990

Survival after conservative resection for T1 N0 M0 non-small cell lung cancer.

Two hundred forty-four veterans, with a mean age of 62.4 years, mainly asymptomatic (pulmonary), were admitted generally for other disease or pension evaluation and underwent lobectomy (131), segmentectomy (107), or wedge resection (6) for T1 N0 M0 lung cancer between 1966 and 1988. Conservative resection was preferred during the past decade. The average lesion diameter was 2 cm. Thirty-day mortality was 2.9%, similar for the three procedures. Absolute 5-year survival, 51%, was 78% if only deaths from the initial lesion are considered; 19% died of comorbidity, and 8% died of second lung cancers. Routine preoperative computed tomographic staging and intraoperative sampling of even normal-sized hilar and mediastinal nodes, conducted after 1982, improved survival (p less than 0.006). Patients with lesions less than 2 cm in diameter (146) did better (p less than 0.04), and those with squamous tumors improved similarly (p less than 0.02). Lesions that communicated with a bronchus (88) were more malignant than those (156) that did not (p less than 0.02), because from that locus undifferentiated nonsquamous tumors metastasized widely. These results suggest that the T1 N0 M0 category is not uniform. Histology, size, and location in the lung are significant variables. Results of conservative resection were similar or better than those of lobectomy. The latter was used more in deep-seated lesions, however, when major intersegmental planes were transgressed, and before modern preoperative and intraoperative staging. The T1 N0 M0 category should include lesions 2 cm or less in diameter as a discrete entity.

Adult↗
PubMed1990

The effect of Streptococcus pneumoniae pneumolysin on human respiratory epithelium in vitro.

Streptococcus pneumoniae culture filtrates and pneumolysin both slow human ciliary beating and damage respiratory epithelium in vitro. A polyclonal pneumolysin antibody bound to sepharose beads removed pneumolysin from culture filtrates and showed that pneumolysin alone was responsible for the effects on epithelium. In a 48-h organ culture pneumolysin caused ciliary slowing and epithelial disruption in a dose-dependent manner down to 5 ng/ml. Comparison of the ciliary slowing activity and pneumolysin concentration in filtrates in a continuous broth culture showed a maximal effect at 16 h (pneumolysin 7.5 micrograms/ml). Later the activity decreased while the pneumolysin concentration increased (8.8 micrograms/ml). This loss of activity was prevented by neutralisation of the acid pH of the culture medium. Eight different culture filtrates produced significant (P less than 0.05) ciliary slowing which correlated (r = 0.95) with simultaneously measured haemolytic (pneumolysin) activity. Substitution of tryptophan (position 433) by phenylalanine reduced the haemolytic and ciliary slowing activity of pneumolysin, but did not affect its ability to activate complement. There was no correlation between the ciliary slowing produced by the culture filtrate and that produced by the autolysate of a particular strain, nor between ciliary slowing and the extent of autolysis or the serotype of the strain.

Antibodies, Bacterial↗
PubMed1990

Outcomes of lower extremity amputations.

In an effort to identify variables that could be used to predict outcomes of amputation, a cohort of 97 veteran amputees with a median age of 64 years who underwent 155 lower extremity procedures during 1984 was followed for 15 months. A high incidence of postoperative complication, revision, and mortality with poor quality of life confirm the serious prognosis of these individuals. Regression analyses indicated that peripheral vascular disease and prolonged preoperative hospitalization were associated with complications. Preoperative gangrene and peripheral vascular disease were associated with the need for revision. Complications, a low body mass index, and multiple diseases were related to death. Those with multiple diseases and extensive atherosclerosis were less likely to walk. Ability to perform activities of daily living was the most important predictor of quality of life. Patients at higher risk for these adverse outcomes need to be identified early in their hospital stay. The involvement of the patient or his or her surrogate in decisions regarding the course of treatment and the level of amputation is essential.

Activities of Daily Living↗
PubMed1990

In vitro and in vivo effects of ribavirin on human respiratory epithelium.

The effects of ribavirin, a broad spectrum antiviral agent, on the structure and function of normal human nasal epithelium have been studied in vitro, as has also the in vivo effect of treatment with nebulised ribavirin on nasal mucociliary clearance of saccharin in four patients. Ciliary beat frequency was measured by a photometric technique, and changes in epithelial and ciliary ultrastructure were assessed by transmission electron microscopy. Ribavirin solution at the recommended concentration of 20 mg/ml had no adverse effects on ciliary activity in vitro; at concentrations of 50 mg/ml and above it slowed ciliary beating significantly and at 60 mg/ml caused ciliostasis associated with epithelial disruption. Nasal inhalation of ribavirin at 60 mg/ml for up to 20 minutes, however, did not slow nasal mucociliary clearance, nor did it adversely affect the ciliary beating or structure of nasal ciliated epithelium examined in vitro immediately after inhalation.

Aged↗
PubMed1990

The effects of activated eosinophils and neutrophils on guinea pig airway epithelium in vitro.

Epithelial shedding is a characteristic feature of asthmatic airways and has been attributed to eosinophil products. We have examined the interaction of purified intraperitoneal guinea pig eosinophils with or without platelet-activating factor (PAF, 10(-7) M) or lyso-PAF (10(-7) M) with guinea pig tracheal epithelium in vitro. At 0, 4, 14, and 24 h, the percentage of ciliation of the tracheal circumference (CTC) was measured by light microscopy and the ciliary beat frequency (CBF) by photometry. PAF-activated eosinophils (50 x 10(6) cells/ml) disrupted the epithelium, mean CBF and CTC being reduced by 77.8 +/- 5.8% (mean +/- SEM; P less than 0.001 versus control) and 94.2 +/- 1.4% (P less than 0.001) over 24 h, respectively. PAF (10(-7) M) alone had no significant effect. Lyso-PAF with eosinophils (50 x 10(6) cells/ml) also reduced mean CBF and CTC but to a lesser extent. Eosinophils alone also led to a reduction of 36.2 +/- 11.4% in mean CBF and 53.0 +/- 15.5% in CTC, but these changes were not significant. The PAF antagonist, WEB 2086 (10(-6) M), significantly inhibited the mean CBF and CTC reduction due to PAF-activated eosinophils by 61.5 +/- 17.2% (P less than 0.01) and 20.8 +/- 6.5% (P less than 0.05), respectively. In addition, catalase (1,125 U/ml) partially inhibited the mean CBF and CTC reduction induced by PAF-activated eosinophils. Intraperitoneal neutrophils (PMN) (50 x 10(6) cells/ml) also disrupted epithelium but to a lesser extent (24-h reduction: 34.2 +/- 12.7% for mean CBF and 60.2 +/- 13.2% for CTC, respectively). Stimulation with PAF (10(-7) M) had no further effect. Marked exfoliation of the epithelial layer was observed after 14 h of incubation with activated eosinophils. We concluded the PAF-activated eosinophils are capable of grossly disrupting ciliated epithelium and may contribute to epithelial damage observed in asthma.

Animals↗
PubMed1989

von Willebrand factor is an acute phase reactant in man.

Plasma von Willebrand factor antigen (vWfAg) concentrations in 19 patients with acute infectious illnesses of bacterial, viral or parasitic origin were significantly elevated with a mean greater than 3-fold above normal. In individual patients the elevation of vWf correlated strongly with the elevation of serum C-reactive protein (CRP). When patients were studied longitudinally, vWfAg and CRP concentrations both returned to normal values over 3-4 weeks. Similarly, in 14 volunteers infected with cold virus, vWfAg and CRP levels rose significantly and fell together during the course of infection. VWf is thus an acute phase reactant in man.

Acute-Phase Proteins↗
PubMed1989

Recent trends in the management of incisional herniation.

There is a high incidence of risk factors for incisional herniation in hospitalized veterans. Almost half the defects appear more than 12 months after celiotomy. "Buttonholing" of the rectus sheath by a sawing motion of the continuous nonabsorbable suture may be responsible for this later herniation. Suturing with synthetic, slowly absorbed monofilament may reduce delayed herniation. The recurrence rate after primary repair was 24.8% (n = 206), and after a second repair the recurrence rate was 41.7% (n = 36). Plastic prostheses, used only in difficult cases (18% of the sample), were associated with a recurrence rate similar to that associated with sutures because of protrusion around the edge. The use of larger and better fixed ("sandwich") polypropylene mesh (Marlex) is indicated. Subxiphoid epigastric hernias following sternotomy do not require prosthetic herniorrhaphy.

Abdomen↗