Epidemiology of COVID-19: What changed in one year?

A coronavirus brought the first pandemic attack of this century as a flu virus did a hundred years ago. This greatest pandemic of the century brings us new opportunities to understand and explore the dynamics of a contagious disease. Nearly two years later, we are still collecting the evidence to understand the disease. Some basic epidemiological properties are still urgently needed. Not only the origin of the virus but also Ro value, possible transmission routes, epidemiologic curves, case fatality rates, seasonality, severity and mortality risk factor, effects on the risk groups, differences between countries and so on still require strong evidence prior to making final suggestions. In this review, we tried to evaluate the epidemiological evidence to scrutinize where exactly we are in this pandemic.     

Signet-ring cell carcinoma of the prostate effectively treated with maximal androgen blockade

Primary signet-ring cell carcinoma (SRCC) of the prostate is very rare and has a poor prognosis, even when treated with aggressive therapy. We report herein a case of a 72-year-old man with prostatic SRCC. The patient had a tumor that extended directly to the rectum. Maximal androgen blockade was started and 20 months later, the patient was alive without evidence of recurrence. The present case of prostatic SRCC responded well to medical therapy, however, tumors can recur after a long period of time. Therefore, adjuvant therapy is recommended.     

Depression–dementia medius: Between depression and the manifestation of dementia symptoms

Depression and dementia, among the most common conditions in clinical practice, sometimes coexist, sometimes succeed each other, and often confuse clinicians. In the present paper, the clinical concept of ‘depression–dementia medius’ (which includes pseudodementia and depression in Alzheimer's disease as exemplars) is proposed, in reference to Janet's concept of psychological tension. Because psychosomatically complex human lives are always in a state of dynamic equilibrium, it seems sensible to propose that pseudodementia and depression in Alzheimer's disease are located within a spectrum extending from depression without dementia symptoms to dementia without depression. From the Janetian viewpoint, pseudodementia is regarded as uncovered latent dementia as a result of reduced psychological tension. Dementia is more than a fixed progressive condition under this view, and is a manifestation of dynamic mental activities. Characterizing these entities through perspectives such as psychological tension may yield deep insights in clinical practice.     

Dynamic ultrastructure of mouse pulmonary alveoli revealed by an in vivo cryotechnique in combination with freeze-substitution

A morphological approach to cell dynamics is usually difficult, since routine preparative techniques for electron microscopy always induce artifacts due to cessation of the blood supply into organs. An in vivo cryotechnique followed by the freeze-substitution method probably reduces such problems. It was applied for examining the pulmonary alveoli of BALB/c mice in vivo. The following ultrastructural features were revealed. (1) A surfactant layer provided a continuous covering to the alveolar epithelium. (2) Pleural epithelial cells, alveolar cells and endothelial cells contained many small vesicles and pits. In the alveolar epithelium, they were often localised near microtubules. (3) Typical lamellar structures in large alveolar epithelial cells were rarely detected. (4) Circulating erythrocytes with various shapes were observed in branching blood capillaries. (5) A close association between erythrocytes and the endothelium was seen at the peripheral alveolar septum. Such ultrastructural arrangements may be appropriate for the physiological functions of the pulmonary alveoli, such as exchanges of gases or materials in vivo.     

Demonstration of the intralobular lymphatics in the guinea pig pancreas by an enzyme-histochemical method

Intralobular lymphatics in the guinea pig pancreas were demonstrated enzyme-histochemically showing the extent, distribution and fine structure by combined light and transmission electron microscopy. 5'-nucleotidase(5'-Nase)-positive lymphatic vessels were present throughout the pancreas. Intralobular lymphatics among the acini were comparatively rare and generally independent of the blood capillaries, pancreatic ducts and acini. These lymphatics revealed the usual structural features, such as typical intercellular junctions and very tenuous vascular walls without continuous basal laminae. Fine precipitates of the cerium-based reaction product for 5'-Nase activity were found to be associated with cell membranes of the lymphatic endothelium and pinocytotic vesicles. Lymphatics were not closely related to the endocrine islets, although alkaline phosphatase(ALPase)-positive blood capillaries were well developed. Collecting lymphatic vessels with valves with weaker 5'-Nase activity were also detected in the interlobular connective tissue. ALPase activity, absent in the lymphatics, was positive in the blood capillaries, suggesting that it is also a useful way of demonstrating, histochemically, the blood capillaries in the guinea pig pancreas.     

Immunogenicity and reactogenicity of the component acellular pertussis vaccine produced by a combination of column purified pertussis toxin and filamentous haemagglutinin

This is the report on a prospective, single blind, comparative study of a component acellular pertussis vaccine produced by a combination of detoxified, column purified pertussis toxin (PT) and filamentous hemagglutinin (FHA) combined with diphtheria and tetanus toxoids (DTcaP) and the traditional acellular pertussis vaccine produced with essentially the same method as described by Sato with DT (DTaP) of the same manufacturer. A total of 616 infants and children received DTcaP and a total of 289 received DTaP. In all age groups for both vaccines values of serum antibodies to PT and FHA after two doses of the vaccines were comparable to those of convalescent sera. Incidences of systemic and local reactions were, in general, not greatly different between DTcaP and DTaP recipients. In Japan the use of traditional acellular vaccines replaced whole cell vaccines in 1981. Protective antigens of Bordetella pertussis have now been specified and thus component vaccines have become theoretically possible. This is the first component vaccine which has been developed in Japan. Several other component vaccines are now under investigation in the world.     

Inflammatory esophagogastric polyp and fold in an adolescent

The case of a 13 year old boy with an inflammatory esophagogastric polyp and ulcerative colitis is described. Endoscopy revealed a typical polyp and gastric fold complex at the esophagogastric junction and a hiatal hernia. Histology of a biopsy specimen confirmed an inflammatory polyp covered by hyperplastic squamous and gastric foveolar epithelium. Continuous 24 hour esophageal manometry suggested gastroesophageal reflux, which may be related to the pathogenesis of the lesion. Follow-up endoscopy showed marked regression of the polyp with medication for reflux eosphagitis. This clinical entity is rare in childhood and adolescence, and the manifestations may not be readily recognized. Therefore, endoscopic biopsy is important in children with esophageal polyps. However, polypectomy is unnecessary except when malignancy is suspected or when symptoms persist.     

Endoscopic ultrasonography in a child with chronic pancreatitis

In a case with chronic pancreatitis and pseudocysts related to muscular cytochrome—c oxidase deficiency, endoscopic ultrasonography (EUS) was performed to morphologically examine the pancreas for features that may have been missed by abdominal computed tomography and pancreatography. Conventional abdominal sonography had failed to show valuable diagnostic information of chronic pancreatitis in this case. EUS demonstrated several new findings. Parenchymal atrophy was remarkable, especially in the pancreatic tail, and a dilated pancreatic main or branch duct was clearly found in the region. Moreover, pancreatic stones in the main duct were also distinctly proved. EUS may become a useful new diagnostic method in pediatric gastroenterology, especially when sufficient findings are not obtained by conventional imaging techniques. However, an ultrasonographic endoscope with a shorter rigid portion and smaller caliber should be developed for pediatric patients.